As Justin Gatlin, the Olympic champion, swept over the line in a UK All Comers' record of 9.89sec, the world record holder, Asafa Powell, was face down on the track scarcely 15 metres from the blocks, felled by a recurrence of a groin injury that now seems certain to deny him a run in the World Championships which get under way in Finland a fortnight from now.
"I felt the injury as soon as I left the blocks," said the 22-year-old Jamaican, who incurred the problem in setting his record of 9.77sec in Athens last month. "It's very serious, and I'm not sure about Helsinki."
But Britain's 400m runner Tim Benjamin is very sure about the World Championships after securing a startling victory over the Olympic champion, Jeremy Wariner, in a personal best of 44.75sec that catapaulted him into world class circles.
Wariner is now receiving guidance from the former world and Olympic 400m champion Michael Johnson, but all the insider knowledge in the world could not resist the charge of the 23-year-old Welshman from lane seven. The American finished a metre behind in 44.86.
"I'm happier breaking into world class and sub 45 than to beat Wariner," said Benjamin, who was flat on his back for a fortnight in hospital last autumn after a lumbar injection went badly wrong. "Britain needs medals and I want to be the one to do it, but please give me time. I'm fed up with people saying I'm not quite world class. I've finally proved it now.'
Gatlin had little to prove last night, but the likely absence of Powell from Helsinki is nothing but good news for him. The 23-year-old American finished with an exuberance that augured well for his hopes of eclipsing Powell's world record. Asked if that mark was now within his reach, Gatlin responded: "I think so," before adding his own special message. "I want to dedicate the race to the people of London. Stay safe - and watch out for terrorists."
Earlier in the evening, Londoners received another tribute from the team which had secured the 2012 Olympics, headed by double Olympic champion Seb Coe, as they were thanked for their support. 'The challenge now is to make the 2012 Games the best ever,' Coe added.
Powell's agent, Paul Doyle, said he would undergo a scan, but added: 'The picture does not look good with the worlds only two weeks away.'
Wallace Spearmon took the 200m for the United States with a stadium record of 19.89sec, with Jamaica's Usain Bolt 0.1sec behind. That pace was too fast for Britain's pairing of Christian Malcolm and Marlon Devonish, who clocked 20.39 and 20.41 respectively.
The triple jump threw up dramatically different fortunes for Britain's leading pair. Nathan Douglas, who won the trials with a personal best of 17.64m last month, confirmed his status as a genuine medal contender for Helsinki with a winning leap of 17.32.
"I produced one of the best series of jumps I've ever done today, so I'm really pleased," said Douglas. 'I proved to everyone that I can jump well under pressure."
With Christian Olsson, the Olympic triple jump champion, out of contention for the World Championships because of a foot injury, the chances for Britain's athletes to make their mark have markedly improved.
But Phillips Idowu was unable to put a marker down for Helsinki as he pulled out of the competition at short notice, baffling organisers by simply failing to turn up.
In the 1500m, the Commonwealth champion Michael East ensured his appearance in Finland by clocking 3min 33.32sec to take third place in a race won by Kenya's Bernard Lagat in 3.33.12.
Meanwhile, the pole vaulter Janine Whitlock, who returned to action this season after a two-year doping ban, achieved the 39th British record of her career with an effort of 4.47m.
Lee McConnell, Scotland's European and Commonwealth 400m medallist, has found life hard going as she attempts to switch to the 400m hurdles event. Although she ran a personal best in finishing second at the world trials, McConnell was still in need of a qualifying time when she lined up for a national event race at Crystal Palace last night, but she came to grief at the seventh hurdle and failed to finish.
Nicole Sanders, who won the trials in 55.61sec, 0.01sec outside the qualifying standard, pulled out of last night's meeting with a stomach problem but intends to book her ticket to Helsinki tomorrow in Belgium.