Gay not concerned despite tasting defeat to his countryman Dix

Gay, competing for the first time since picking up a hamstring injury while setting a world 200m record on a straight track in Manchester seven weeks ago, looked to have the race won. But Dix, the Beijing Olympic bronze medallist over the distance, produced a final spurt to win by 0.04secs in 19.72 seconds - a new Prefontaine Classic meeting record.

However, Gay insisted he was satisfied with his performance.

"I was pretty nervous, it was my first 200m (in a stadium) in over a year," said the 27-year-old, who is scheduled to face Asafa Powell over 100m at the British Grand Prix in Gateshead on Saturday.

"I came away with no injuries. I felt no pain from my hamstring and I'm feeling good. My confidence is cool. I don't like to lose but I feel okay.

"The performance wasn't bad for my first race and I was under a lot of pressure.

"I felt him coming up on me on the curve and I knew I was in for a tough race. It's not quite the step I wanted but I know my finish is not there yet."

Ryan Bailey completed a USA clean sweep by taking third place in a personal best time of 20.17secs.

The women's 100m was equally exciting, Veronica Campbell-Brown producing a lifetime best and the fastest time in the world this year of 10.78secs. The contest developed into a race of three at the halfway point when the two-time Olympic 200m champion got her nose marginally in front.

Campbell-Brown then edged visibly clear in the next 30m as Olympic and world champion and fellow Jamaican Shelly-Ann Fraser along with Carmelita Jeter tried to stay in touch. But Campbell-Brown's final surge saw her score a solid victory with a new meeting record mark.

Fraser got the better of American Jeter but only by 0.01s in 10.82secs as the pair, both with season's bests, also bettered the Prefontaine Classic time of 10.94s which Torri Edwards achieved two years ago.

There were also four other world-leading performances. Olympic bronze medallist David Oliver clocked 12.90s to win the 110m hurdles, equalling the fourth fastest time ever. Only world record holder Dayron Robles (12.87) of Cuba and former holder Liu Xiang have run faster than the Olympic bronze medallist, who equalled Dominique Arnold's national record.

"I didn't get a great start but I brought it home," Oliver said.

The American, who clocked the quickest time of the season and has set lifetime bests in his last two races, pushed countryman Ryan Wilson (13.16) into second spot.

Chris Cantwell claimed victory in the shot put with a throw of 22.41m, Abubaker Kaki won the 1000m in 2mins 13.62secs while Russia's world indoor champion Mariya Savinova triumphed in the women's 800m in 1:57.56.Jamaican Veronica Campbell Brown, the Olympic 200 champion, surprised a talented 100m field with a personal best and season-leading 10.78 seconds.

Olympic 100m gold medallist Shelly-Ann Fraser trailed in 10.82, just ahead of American Carmelita Jeter (10.83).

World indoor champion Mariya Savinova of Russia clocked a third season-leader when she beat Olympic 1,500m gold medallist Nancy Langat of Kenya in a time of 1:57.56.

Ethiopian world record holder Tirunesh Dibaba opened her 5,000m season with a win in 14:34.07.

Barbara Parker, the only Briton at the meeting, finished sixth in the 3000m steeplechase with a personal best of 9mins 35.17secs. Kenyan Milcah Chemos won in 9:26.70.

•Paula Radcliffe finished a charity 10km run yesterday, despite being seven months pregnant.

The world record holder for the distance ran the race in Leeds, Yorkshire, for the Jane Tomlinson Appeal which raises money for children's and cancer charities.

She completed the course in 45mins 35 secs and ran the final 100m with her daughter Isla Lough. The 36-year-old said: "It was a fantastic occasion and I had a lot of fun.

"It's a tough course and we have to say thank you to all of the people who turned out today.

"I run every day and it felt good. I was not concerned about running a time, it was about enjoying the day.

"There were people cheering all the way round, the atmosphere was great."

Radcliffe, who ran 10km in the fastest ever time of 30 minutes and 21 seconds in 2002, paid tribute to Jane Tomlinson, who set up the charity before she died of cancer.

She said: "Jane Tomlinson was such an inspirational person, she never let anything get her down, and this race is really in her image.

"It is about something so serious but it deals with it in such a positive way, with a lot of joy for a lot of people.

"I've not done this event before but I have known Jane since 2002 and she was a great person."