Keogh scored in each half of the 4-2 win against Melbourne Victory, who finished the game with nine men at nib Stadium, to take his tally to five goals for the tournament – adding to the four he has in the A-League.

While De Silva's strike in the 13^th minute of extra time after scores were tied at 2-2 at the end of regular time, was the 17 year olds' first goal for the club.

The real cost of the loss to the Victory is unknown though.

As well as being put out of the tournament, they will limp back to Melbourne with injuries to key players, while Daniel Georgievski and Adrian Leijer will also miss Monday's A-League clash against Wellington after receiving two yellow cards each (which resulted in red cards and expulsion from the game) on Wednesday night.

The Victory will also be eagerly awaiting the fitness of key players ahead of the clash against the Phoenix at AAMI Park.

They could be short some strike power with concerns over the fitness of Archie Thompson and Besart Berisha.

Thompson took no part in the game after pulling out during the warm-up, while Berisha was subbed out of the contest one minute before half-time with what appeared a groin injury.

The pair have scored seven of the Victory's 10 goals in the first three round of fixtures.

However, it was still the Victory that got the fast start on Wednesday night, with Ben Khalfallah smashing one to the left of a diving Danny Vukovic from 25m in the eighth minute.

Hersi had a couple of realistic chances to level the scores for the Glory, but his first touch on both occasions wasn't great.

He did draw the penalty in the 14^th minute that saw the game tied up at half-time. Leigh Broxham held him by the arm a little too long in the box and Keogh made no mistake from the spot.

That was the first goal scored against the Victory in this competition

The second nearly came in the 70^th minute when Richard Garcia flicked the ball perfectly to Keogh who was alone in the box with just Nathan Coe in front of him, but the Irishman nodded the ball over the crossbar.

He made no such mistake on in the 82^nd minute though when left unguarded at the back of the pack at a Glory corner. Scott Jamieson took the kick and found Keogh, who was given too much room by Melbourne's Andrew Nabbout.

It looked as though the Glory was heading for the semi-finals from there, but a 25m stinging shot from a Guilherne Finkler free kick in the 92^nd minute found the corner of the net to level the scores again.

Seconds before extra time was called Hersi almost claimed victory for the home side, but his bullet from outside the box smashed into the side bar and just failed to fall over the line.

Keogh may not have scored in extra time, but he played a part in both Perth goals.

He laid off to Da Silva for his score and did the same for Nebojssa Marinkovic 12 minutes later, who made no mistake and finally sealed the result.

Perth joins Central Coast Mariners, Adelaide United and NPL team Bentley Greens in the semi-finals. The draw will take place live on Foxsports on Friday afternoon.