At around 4.30pm, Nathan Lyon, playing his 100th consecutive Test, set off to chase a ball towards the Grand Stand boundary. He pulled up and started to limp, a few moments later he was hobbling towards the dressing room. England were 182 for 1 and Australia had, at least for the day, likely the match and maybe even the series, lost a specialist bowler, one with 496 Test wickets to his name. If you wanted any more comparisons to 2005, was this the Glenn McGrath moment?
It had already been a day where Australia had let slip their grip on the contest. It had started late on the first evening when they handed two wickets to Joe Root shortly before the second new ball. Although Steven Smith crafted a superb century, the slide continued on Thursday morning and in all their last seven wickets fell for 100. From England's point of view a total of 416 isn't a great result when you've asked a side to bat, but they had not been shut out the way Smith and Travis Head had threatened to.
A few hours later, Lyon was being helped off the field, a fate he had avoided since being recalled midway through the 2013 Ashes - the corresponding fixture on this ground was the last Test he did not play. The sun was breaking through the clouds, the pitch was looking flat, England's second-wicket pair of Ben Duckett and Ollie Pope had put together 91 in 20 overs at that point and Cameron Green was struggling to keep his foot behind the line.
Pat Cummins knew there would be times when he would be challenged in this series. There had been some at Edgbaston, but here was one he would have hoped to avoid. With frontline spin not an option, they went for the short-ball plan and England obligingly helped them out. There was more than a hint of Ben Stokes' own Bazball tactics in the way Cummins marshaled his side. Not that England's batters needed much persuading, but he dared them to take it on with fielders scattered in the deep and they were happy to roll the dice. It was only Stokes, himself, who brought a modicum of calm to proceedings.
"We felt like we were in the game for a lot of the time there," Smith said. "Until probably Stokes, he came out and he was starting to duck under a few, but we were setting the fields and they were taking it on and creating opportunities.
"It was interesting. Most of the fast bowlers, they probably wouldn't want to keep charging in bowling the short stuff but while it looked as likely as it did, on a pretty benign surface, it was the right way to go. If you get under a few then might stop doing it. They kept taking it on and kept presenting opportunities for us."
Pope picked out deep square leg, Duckett found long leg two short of a second century at Lord's and Root was brilliantly caught by Smith at backward square leg having been given a life second ball when Green overstepped in the same over he claimed Pope. All of a sudden it was 222 for 4 and Australia's predicament was not quite so bad. It would have been 243 for 5 had Marnus Labuschagne not spilled Harry Brook at square leg on 25.
However, barring a remarkable recovery from Lyon overnight Australia face the rest of this game without someone who has been ever present, and recently a consistent matchwinner. Green, bowling at Lord's for the first time, sent down six no-balls in his seven scattergun overs but the importance of his presence in Australia's attack has grown significantly in the light of Lyon's injury.
He will at least allow Cummins to spread the load between himself, Mitchell Starc and Josh Hazlewood - whose energy levels will soon be depleted if they have to sustain the short-ball approach - with some help from Head's not-to-be-underrated offspin. The last over of the day was sent down by Smith, and could it be that he has a role to play on the ground where he began as a legspinner in 2010 (and claimed his career-best 3 for 18 in 2013)?
Australia's bowlers have accepted they will need to look at their bowling figures in a different light during this series. At one stage Starc, who had briefly found some swing with the new ball, was conceding seven an over but as he did in the World Test Championship final, where he claimed Virat Kohli, found a way to claim the big prize of Root. Hazlewood dragged his economy back from above a run-a-ball.
When Lyon left the stage, he was conceding just 2.69 an over to further highlight the role he was playing. England did show Head's offspin significant respect as Stokes brought an element of balance to the innings in the closing half an hour, although that could be different when there isn't stumps to play for.
England, you would assume, will have a run chase to try and win this match at some stage in the next few days. The early history of Bazball was defined by their inhibitions of hunting down big targets last season against New Zealand and India. Most likely Australia will not have their frontline spinner. Lyon's injury hasn't quite defined the game yet, but it might yet do so if England's batters don't offer the visitors a way out.