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Bolt could afford to ease up over the last 20 metres in a convincing win
Usain Bolt underlined his Olympic credentials with a stunning victory in the 200m at the London Grand Prix.
The 100m world record holder eased home in 19.76 seconds ahead of Wallace Spearmon and Ireland's Paul Hession.
There were wins for British duo Marilyn Okoro and Martyn Rooney in the women's 800m and men's 400m respectively.
Mo Farah disappointed in the 3000m but Greg Rutherford sealed victory in the long jump, and Kelly Sotherton won her two-day, four-event contest.
Bolt blew away the competition to register a new British all-comers' record at Crystal Palace, leaving second-placed US star Spearmon trailing half a second back at the line.
"Looking to Beijing, I think I have a good chance in the 200m and 100m - I'd love to do both," said the Jamaican.
"I'm still waiting to see what will be going on with that, my coach is making that decision maybe in a week or so.
"As for here, the crowd is wonderful. These guys come and support me and I have to put on a good show for them. I look forward to coming here every year."
At a meeting where British track athletes largely failed to inspire, the performances of Okoro and Rooney shone through.
Okoro smashed her personal best to win her 800m contest in a time of 1:58.45, having surprised the field with a level of pace nobody else could match.
"I was expecting to run fast," Okoro told BBC Sport.
It was great to do it at Crystal Palace, I'm the local boy and it's great to run a PB here. I'm just so happy
Martyn Rooney, 400m winner
"All the endurance training I did over the winter has paid off and I think I'm ready for Beijing."
Rooney eschewed raw pace for a relentless, powerful performance in the 400m, breaking away on the home straight to record a similarly emphatic win in a time of 44.83.
"That was perfect," said the 21-year-old, who grew up in nearby Croydon.
"It was great to do it at Crystal Palace, I'm the local boy and it's great to run a PB here. I'm just so happy.
"I've been in this shape all season and I needed to get in a race where I was going to be challenged, then taken around in a good 300m time. I knew it was coming and today's the day to do it."
Rutherford shrugged off a poor start to win his long jump competition, leaping 8.16m.
Rutherford scared spectators, already wary following injury to fellow GB jumper Chris Tomlinson, when he applied ice to his leg immediately following his win.
"There's no problem at all, it's just precautionary stuff," insisted Rutherford when questioned about the ice pack.
"I do it after every session," he added, confirming he had come through the event in good shape.
It hampered me a lot and I'm not very happy about that, it could have been a major injury for me
Kelly Sotherton, on suffering an injury following Friday's hurdle debacle
"There's nothing wrong, I'm just making sure it stays nice and calm down there."
Tomlinson could be a doubt for Beijing after landing awkwardly on a jump and immediately clutching his right ankle.
"It's very sore at the moment, I'm absolutely devastated," said the World Indoor Championship silver medallist.
Sotherton also endured an injury scare as a result of Friday night's hurdle debacle, in which the obstacles for her race had been placed in the wrong positions on the track.
But the heptathlete regained her composure to finish second in both the shot put and the 200m, enough for an overall victory from her four events.
"Nobody wanted me to run today - physio and doctor - but I felt OK," said Sotherton, alluding to a slight strain picked up while leaping a wrongly-placed hurdle.
"It hampered me a lot and I'm not very happy about that, it could have been a major injury for me. But I still won."
British entrants, including GB record holder Montell Douglas, were predictably outclassed in the women's 100m, Jamaican star Veronica Campbell winning the final in a time of 10.86.
British Olympic reject Richard Yates smashed his 400m hurdles PB
Farah's 3000m race will have worried the 25-year-old, who came home sixth having struggled with the pace, and Goldie Sayers had to settle for second place in the javelin, throwing 63.82m to finish behind Germany's Christina Obergfoll.
Rick Yates, the men's 400m hurdler whose omission from the GB Olympic team sparked the formation of a Facebook protest group, showed the selectors his mettle with a fine second-place finish.
Yates, veins bulging, produced a magnificent personal best of 49.06 to cross the line behind America's Kerron Clement.
The men's 4x100m relay rounded off the 2008 Grand Prix and was won in style by one of two US teams, in the fastest relay time of the year - 37.80.
A British team of Christian Malcolm, Tyrone Edgar, Marlon Devonish and Craig Pickering finished third, a result that appeared to satisfy the athletes.
"We didn't win but it's good preparation," said Devonish, while Pickering promised the team would "try to improve" for Beijing.