EUGENE, Oregon - Kenyan-born Bernard Lagat won the men's 5,000 metres at the US trials to make his first American Olympic team and Bryan Clay produced a personal best in the decathlon on Monday.

Bernard Lagat celebrates winning the men's 5000 meters final at the US Olympic Track and Field Trials in Eugene, Oregon June 30, 2008. [Agencies]

"This is a dream come true," the 33-year-old Lagat told reporters. "Now, I'm part of the USA going to Beijing."

Lagat, who became a US citizen in 2004, won the 1,500 and 5,000 world titles for his adopted country in 2007 but this was his first opportunity to earn an American Olympic vest.

"The Olympics are the biggest," Lagat said. "Being on team USA is wonderful, fantastic."

Twice an Olympic medallist for Kenya in the 1,500 metres, Lagat ran conservatively until 200 metres from the end before surging clear to win by more than 10 metres in 13 minutes 27.47 seconds.

He is also expected to run the 1,500 metres at the trials before deciding what to do in Beijing.

Matt Tegenkamp was second in the 5,000 in 13:29.68 and Ian Dobson took third in 13:29.76.

CLAY IMPRESSIVE

Olympic silver medallist Clay won the decathlon with a life-time best of 8,832 points, the best score in the world for four years.

"I think there is tons of room for improvement," Clay said. "I think this just goes to show everybody mentally I am a very tough competitor."

Trey Hardee took second with 8,534 points and former world champion Tom Pappas third on 8,511 to make his third Olympic team.

Olympic newcomers Nick Symmonds and Andrew Wheating led a stirring 800 metres final. Symmonds broke through over the final 120 metres to win in 1:44.10 and the 20-year-old Wheating, a local college student, took second in 1:45.03.

Olympic and world champion Jeremy Wariner outpaced top challenger LaShawn Merritt to win their 400 metres semi-final in 44.66 seconds. Merritt clocked 44.76.

The women's best 400m runners also advanced. Mary Wineberg won the opening semi-final in 50.57 seconds with Beijing favourite Sanya Richards taking the second semi in 50.75.

The trials take a two-day break beginning on Tuesday. Competition resumes on Thursday for the final four days.