On the first day of track and field action at Hayward Field in Eugene, Rupp – an Olympic silver medallist at London 2012 behind training partner Mo Farah - looked fully at home on his local track as he secured his eighth US 10,000m title in boiling heat that caused several runners to drop out.

U.S. Army World Class Athlete Program runners Shadrack Kipchirchir and Leonard Korir finished second and third to qualify for their first Olympic team.

Lagat dropped out dramatically in the 81 degrees heat after being passed for third place.

Rupp, the US record holder won with a time of 27min 55.04sec ahead of Kipchirchir, who was second in 28:01.52. Korir claimed the third place on the US Olympic team with 28:16.97.

"The 10,000 is definitely kind of my baby so I didn’t want to lose it here," Rupp said.

Lagat, a naturalised Kenyan who won Olympic bronze and silver medals at the Sydney 2000 and Athens 2004 Games in the 1500m, failed to finish the race. 

He still hopes to compete in the 5,000m, which is due to start on Monday (July 4). 

Rupp ran 26.2 miles for the first time in February at the US Olympic Marathon Trials – and he won, earning an Olympic berth in the event. 

He may choose not to do both the events he has qualified for at Rio 2016.

The 10,000m is due to take place on August 13 and the marathon is being held on August 21.

Olympic 200m champion Allyson Felix, who has been troubled by an injury to her right ankle this year, showed no obvious signs of distress as she eased through her opening 400m heat to keep her ambition of doubling up in Rio alive.

But for the woman who took Olympic gold in London over 400m, Sanya Richards-Ross, the evening ended in pain and tears.

The 31-year-old, who planned to retire after Rio 2016, was forced to a halt after 250 metres by a tightening hamstring.

“I’ve had an amazing career,” said Richards-Ross.

 “To have my last race be here, at Hayward Field, in front of these fans, it’s incredible.”

It was the second race at Hayward Field  in five weeks for Richards-Ross, who holds the track record.

She could only finish seventh in the Prefontaine Classic, Eugene’s International Association of Athletics Federations’ Diamond  League meeting.

World shot put champion Joe Kovacs, who missed out by one place at the last US Olympic trials, made no mistake in tonight’s final as he secured his Rio 2016 place with a best effort of 21.95 metres, although he had to settle for second place behind  Ryan Crouser, who threw 22.11m.

Kovacs, who earned his gold medal in Beijing last summer after a titanic struggle against Germany’s defending champion David Storl, will be joined in Brazil by fellow Pennsylvania thrower Darrell Hill, who took the third qualifying spot with a best throw of 21.63m.