Nathan Lyon sparked another confrontation between Australia and England on a day he became Test cricket's leading wicket-taker for 2017.
The man dubbed the "GOAT" dominated proceedings in Adelaide on Monday, claiming four wickets, taking one of the catches of the summer then frustrating England with his stalling tactics in the final over of the day.
Lyon's one-handed stunner to dismiss Moeen Ali came as England lost a cluster of wickets chasing Australia's imposing first innings total of 442.
Although England's bowlers fought back under lights, Australia finished the day with a lead of 268 and well placed to wrap up victory in the next two days.
Playing as a nightwatchman, the off-spinner denied England an extra over by appearing to be hurt after being struck by paceman Chris Woakes.
While most batsmen tend not to show pain when hit, Lyon was eager to run down as much of the clock as possible as he recovered from the blow. Australia even sent out a member of its medical staff to check on Lyon, who was on his haunches.
The two sides exchanged words on their way off the field, with England captain Joe Root and Australian batsman Peter Handscomb in the thick of it.
Umpire Aleem Dar was less than impressed, standing between the two in a bid to defuse the situation.
Woakes labelled Lyon's tactics as "time wasting" but did not believe he had done anything illegal.
"It's within the rules. If we're in the same position, I don't see why we wouldn't try and do anything different," Woakes said.
"Everyone tries to get an edge on the opposition somehow, and under lights you wouldn't want to face an extra over. I don't blame them, really.
"It's Ashes cricket, you're expecting plenty of verbals out on the field. I don't think there's much wrong with what the Australians have done. It must be exciting to watch. It's great to be out there amongst it."
Mitchell Starc denied Lyon was guilty of gamesmanship, saying his teammate was genuinely hurt.
"It's never nice to be hit with a cricket ball," Starc told reporters. "I'm happy to bowl a few at you lot if you like. He did well to close out he day."
Lyon's fourth wicket, that of James Anderson, took him past South African speed demon Kagiso Rabada to 55 wickets for the year at a miserly 22 apiece. He is one of six spinners in the top eight.
Such a transformation was hard to see this time last year when he was down on form and confidence and seemingly on his way out of the Test arena.
The turnaround started at this venue against South Africa when he claimed three quick wickets under lights to swing the match back in Australia's favour.
But it was on the subcontinent where Lyon roared, producing career-best figures against India in Bangalore before mesmerising Bangladesh with 22 wickets in two Tests.
"He's definitely got a lot of confidence at the moment and it's helping the rest of the bowlers out," Starc said.
"He's bowling a lot more overs, taking a lot more wickets, and has that belief in himself he can get a wicket most balls.
"It's something he may not have had in the past. You'd have to ask him what was going through his mind 12 months ago but at the moment he's loving his cricket and putting the ball where he wants to a lot of the time.
"He's in the game all the time. It's great to watch, it's great to be a part of, it's helping a lot of the bowlers out when you have a world class spinner from one end and allowing three guys to rotate from the other, it's easy for everyone."