Charles Jock, a recent UC Irvine graduate, won his first-round heat of the 800 meters in the U.S. Olympic Trials at Hayward Field in Eugene, Ore., on Friday.

Jock recorded a time of 1 minute, 47.90 seconds in rainy conditions with Michael Rutt (1:47.99) and Michael Preble (1:48.20) finishing second and third in his heat.

Tyler Mulder of Oregon TC Elite had the fastest overall qualifying time of 1:46.81.

The semifinals of the 800 are at 4:45 p.m. Saturday with the top eight advancing to the final Monday at 7:47 p.m. The top three from Monday's final will earn spots on the U.S. team for the London 2012 Olympics.

Jock, a three-time All-American and Big West Conference Track Athlete of the Year, won the NCAA title in the 800 with a time of 1:45.59 at Des Moines, Iowa, June 8.

Jock, who also won this year's Big West 800 title, was a member of the U.S. team for the IAAF World Championships last summer. He finished third in the U.S. Trials last June in Eugene with a school-record time of 1:44.67. Nick Symmonds and Khadevis Robinson were first and second in the 800 at last year's trials and both are entered again this year.

Symmonds and Robinson, along with Jock's Big West rival, Ryan Martin of UC Santa Barbara, also moved on to Saturday's semifinals at the U.S. Olympic Trials.

Sharon Day, a former Costa Mesa High standout, begins competition in the heptathlon June 29.

— From staff reports