The world watched in shock as drug agency USADA found seven-time Tour de France champion Lance Armstrong's career was made by a systematic blood doping campaign.

He was stripped of his titles, while his lucrative corporate sponsors walked away, leaving his reputation in tatters.

While Armstrong was left in disgrace, Sergio Aguero became a hero by scoring a nailbiting 93rd minute goal to secure Manchester City's first English league title since 1968 and Chelsea captured the European Champions League crown.

Great Britain track star Mo Farah joined sprinting great Usain Bolt as the headline acts at the London Olympics, while the UK was also captivated by the feats of unbeaten champion thoroughbred Frankel, now regarded among the best of all time.

TIM BARROW relives the biggest moments in world sport of 2012, as voted by the Mercury sports team.

1. Scandal leaves reputation in tatters

Once revered, Lance Armstrong's empire came crashing down after being stripped of his seven Tour De France titles for the widespread doping scandal which rocked world cycling this year.

The fallout goes on, with Armstrong in disgrace as the evidence against him continues to mount.A document of more than 1000 pages was released by the United States Anti-Doping Agency condemning Armstrong and the US Postal team and banning him from the sport for life.

"The evidence shows beyond any doubt that the US Postal Service Pro Cycling Team ran the most sophisticated, professionalised and successful doping program that sport has ever seen," USADA chief executive Travis T. Tygart said.

Armstrong had denied wrongdoing after years of whispers and allegations, instead focusing on the Livestrong Foundation and fundraising activities, after he beat cancer to win the now tainted Tour de France titles. 

Nike were among the big-name sponsors to walk away from Armstrong, with predictions he could lose as much as US$50 million in the next five years.It may take many more years for professional cycling to recover.

2. Bolting in

There is a remarkable hush in a stadium of 80,000 people in the moments before the men's Olympic 100m sprint final, the anticipation unlike any other event in the world.

For any murmurs lingering as the athletes take their mark, there is a blunt 'shoosh' noise to extinguish it nearby.

Then the track - and the crowd - explodes into life.

The expectation was heavy on the fastest man in the world, Usain Bolt, to win the 100m final in style.

It took the Jamaican about 80m to assert his authority, but in the final strides his dominance in London was breathtaking.

Bolt also claimed 200m gold and the 4x100m relay final with countrymen Yohan Blake, Nesta Carter and Michael Frater.

At various times he produced his signature pointing celebration move, the Mo-Bot (mimicking Mo Farah's love heart-shaped arms above his head) and used a photographer's camera to take photos after winning the 200m crown.

In the greatest show on earth, he was a production all of his own.

3. Finally, a world title

Four times Joel Parkinson had finished second in the world championships.

It seemed like the crown he craved might forever elude him while he surfed in the shadow Kelly Slater.

But after 12 years on the tour, Parkinson's finally arrived, though it took a bit of convincing him.

"I honestly cannot believe this has happened," Parkinson said.

"Hold me up. I'm tripping out, it's surreal, it's like time is going backwards. I've been on the tour for 12 years and the big dream has always been to get a world title. The other dream has been to win at Pipe. Both of those have just come true and I don't even know what to say."

Adding to the extraordinary finish to the title race, fellow Aussie Josh Kerr was rushed to hospital at the Pipeline Masters in Hawaii, amid fears he'd broken his neck after being smashed by a wave while competing.

But he returned given the all clear and returned to compete in the quarter finals, before beating 11-time champion Slater in the semis to secure the crown for Parkinson.

4. Murray's magic moment

After four hours and 54 minutes of the US Open final, Scotland's Andy Murray finally shed the gorilla from his back.

Murray had watched a two-set lead against Novak Djokovic disappear, but found something in the fifth which he'd never summoned before.

Time and again Murray had threatened to win a tennis major and kick down the door to which the top three - Djokovic, Roger Federer and Rafael Nadal - had previously held the keys to, winning 7-6 7-5 2-6 3-6 6-2.

"I'm thinking a lot just now. I'm thinking a lot about a lot of different things. It's hard to explain," he said after holding the US Open trophy for the first time.

"It's been a long, long journey. I don't know if it's disbelief or whatever.

"I'm very, very happy on the inside; I'm sorry if I'm not showing it as you would like."

Under new coach Ivan Lendl, regarded as the greatest player never to win Wimbledon, they had overcome all the mental hurdles, as much as the opponent on the other side of the net.

In truth, the watershed moment had come when he thumped Federer 6-2 6-1 6-4 to win London Olympic gold at Wimbledon, having lost to the Swiss great on the same court in the All England final weeks previous.

5. The greatest of them all

ARRIVING on the world stage as a 15-year-old in Sydney in 2000, US super fish Michael Phelps bowed out in London by winning an 18th Olympic gold.

In total, Phelps claimed 22 medals across four Games.

He capped off his remarkable career by beating countryman Ryan Lochte in the 200m individual medley, just 0.27 seconds outside his own world record.

The result left him frustrated as much as satisfied.

"Someone told me with 25m to go that I was under world record pace. It's a little frustrating I fell a little short," Phelps said.

"But to win the gold medal and be the first to three-peat, I think it's something pretty special and something I'm happy for."

Earlier in the London campaign he missed out on an Olympic medal for the first time in his career, finishing fourth in the 200m butterfly.

But his legend is undeniable.

"Through the ups and downs through my career, I've still been able to do everything that I wanted to accomplish," he said in London.

"I've been able to do things that nobody else has ever done, and that's something I've always wanted to do.

"The memories that I've had from this week will never go away, and soon enough they'll be on a piece of paper and in my journal, and I'll have them written forever."

6. Mo-bot is unstoppable

FEW athletes captured the imagination like Mo Farah in London. He became the great British hero of the Olympic campaign by backing up his 10,000m victory with success in the 5000m event.

Farah's celebrity was complete when he was photographed with sprint champ Usain Bolt - the Jamaican mimicking the Mo-bot celebration of the "M" shaped arms above his head.

"It's unbelievable. Two gold medals, who would have thought that," Farah said.

Farah did sit-ups on the track after winning the 5000m, seemingly effortlessly after being pushed all the way by Ethiopian rival Dejen Gebremeskel and Kenyan Thomas Pkemei Longosiwa as they sprinted down the home straight.

Days earlier, the 29-year-old won the 10,000m in the same hour his fellow British athletes Jessica Ennis won the heptathlon gold and long jumper Greg Rutherford was also victorious.

The crowd in the Olympic Stadium were in raptures as Farah produced one of the moments of the Games.

"I just can't believe it, the crowd got so much behind me and was getting louder and louder," he said.

"I've never experienced anything like this - it will never get any better than this, this is the best moment of my life.

"It doesn't come round often and [it's great] to have it right on the doorstep and the amount of people supporting you and shouting out your name."

7. City over the blue moon

Having waited 44 years, what was another 93 minutes to wait for Manchester City to secure the English league title again?

Leading bitter rivals Manchester United on goal difference heading into the last day in May, City looked to have blown their chance when trailing 2-1 to a 10-man QPR at Etihad Stadium, while the Red Devils led 1-0 against Sunderland.

Edin Dzeko provided hope with a headed equaliser, before superstar striker Sergio Aguero wrote his name into the history books with the most dramatic finish in Premier League history.

Searching for the winner they needed for victory, City launched one last assault on a defiant QPR - who themselves had survived a relegation battle in a stunning final round.

The controversial Mario Balotelli dragged the ball into Aguero's path, then for a moment time seemed to stand still, before the Argentinian blasted home the premiership winning goal in injury time.

Commentator Martin Tyler probably captured it best.

"Aguerrrrroooooooooooo," he exclaimed. "I swear you'll never see anything like this ever again. So watch it. Drink it in. Stupendous."

City are again chasing United in the 2012-13 title race heading into the New Year.

8. US Dream Team's Olympic glory

THEY had been tested in pursuit of a gold medal which most thought would inevitably be theirs, but the US Dream Team maintained their air of invincibility in London.

Spain refused to be merely fodder for the Americans in the final, but the class of the NBA talent proved to be too much to handle, winning 107-100.

For several minutes, the plucky Australian Boomers team - featuring the nation's own NBA star Patty Mills - had also risen to the challenge against the US in the quarter-finals.

Led by Mills and Joe Ingles, the Boomers went on an 11-0 run in the second half to be within three points of the US.

But the Americans responded, winning 119-86.

They would not be denied, holding off the fierce Spanish inquisition to claim the gold.

"This here is right up there at the top of anything I have ever achieved in basketball and it was very emotional standing on top of the podium," Kobe Bryant said, who has won five NBA titles and has been an NBA All-Star in 14 of the 15 seasons he has competed.

"It has been some journey to be standing there at this stage of my career representing my country against such a tough opponent and I will treasure the memory.

"Time is fleeting and the Olympics are very special. We have a lot of talented players coming up and I would want them to keep our traditions up in the Olympics.

"They must have their time as well."

9. Chelsea are kings of Europe

With what turned out to be his last kick for the club, Didier Drogba's penalty ensured the unlikely European Champions League triumph for Chelsea in May.

Manager Roberto Di Matteo had taken over just three months previously and would be sacked before the year was out, but masterminded one of the most memorable and nerve-racking wins in English football history.

Thomas Muller had scored for Bayern Munich in the 83rd minute of the final and it seemed Chelsea would be forced to relive the memories of their 2008 defeat.

Then Drogba equalised five minutes later with a header to force extra-time.

Chelsea had already survived a most searching test from Barcelona in the semi-finals to advance to the final day of the competition.

"It means everything, this competition," Frank Lampard said. "We've been so many years trying to do this. This is the one we really wanted and we've got it. He [Di Matteo] took us from a struggling team maybe going out of the Champions League and we won it, so look at that."

Di Matteo - who was replaced by Rafa Benitez in November after a rollercoaster start to the 2012-13 Premier League season - said Chelsea had made amends for 2008, when John Terry missed a penalty against Manchester United in the final shootout in Moscow.

"I'm enjoying this moment and I'd just like to go out and celebrate with the players," he said.

"I just want to enjoy it. Four years ago the club had a very painful experience in Munich."

10. Flying Frankel a phenomenal track force

The best ever? Maybe.

The best of Britain? Probably.

Horse racing's pin-up of 2012? Absolutely.

The numbers just about say it all - 14 wins from 14, the highest-rated horse in the history of Timeform ratings and the most consecutive European Group 1 wins in history.

For a sport entrenched with numbers, figures alone can't be used to measure this lightning strike of a horse.

Just watch the Queen Anne Stakes on the opening day of the Royal Ascot carnival.

Accelerating so quickly and sapping every last ounce of fight out of his downbeat rivals, jockey Tom Queally was almost launched into the next suburb.

The beaten brigade, headed by regular punching bag Excelebration, were a jaw-dropping 11 lengths astern.

A crowning moment of a career we are never to see the like of again, most predict.

Much like his kindred spirit, the southern hemisphere's wonder mare Black Caviar, naysayers have whispered mutterings about not being taken too far out of a comfort zone and the like.

Frankel never raced outside of Britain, but an ailing Sir Henry Cecil stretched him out to 2200m in his penultimate start, the International Stakes at York. He ambled home by seven lengths.

Success as a stallion, barring any major misfortune, is almost ensured. His racing legend is already confirmed.