Greer, a senior from Lake Oswego, Ore., navigated his was to a second place finish in the first round of the men's 800. The 2013 NCAA indoor and outdoor national champion at that distance advanced to Friday's semifinals in 1:46.66.
In a tactical 1,500 meter semifinal, Fleet stayed out of trouble to finish second and advance to Saturday's final. The junior from San Diego, Calif., timed 3:49.60.
Also in the men's 1,500, senior Brett Johnson, who redshirted the 2013 outdoor season, ran 3:43.07 and senior Patrick Todd timed 3:49.57, but neither advanced.
Mike Berry had one of the more impressive performances among the current Ducks, winning his 400 meter first round heat to advance to Friday's semifinal. The junior from Seattle, Wash., just missed a seasonal best in winning in 45.58.
"I just wanted to get out hard," said Berry. "At 80 meters I wanted to float on the backstretch and go hard in my last 120 and make sure I got top three."
NCAA runner-up Laura Roesler kept her season alive with a second-place finish in the opening round of the women's 800 meters. The junior from Fargo, N.D., timed 2:02.16 to advance to Friday's semifinals.
"I've been really close the past few years, so I don't want to get left out of (the final)," said Roesler. "This is one of the faster times I've ever run, so to run that in a prelim is a good progression."
In her first outdoor race in an Oregon uniform, senior Alexi Pappas finished third in her 3,000 meter steeplechase semifinal to advance to Saturday's final. The transfer from Dartmouth broke 10 minutes – 9:58.89 – to qualify for the final.
Former Duck and current volunteer assistant coach Kimber Mattox will join Pappas in the steeplechase final. Mattox was sixth in the same semifinal in 10:06.33, but was able to advance on time.
Other results from current Ducks on Thursday included freshman Jenna Prandini, who ran 11.90 in her heat of the 100 meters, and senior Becca Friday, who finished her final 1,500 meters as a Duck in 4:27.07. Neither runner advanced.
In the junior portion of the USA Championships, freshman Brittany Mann finished fifth in the women's shot put with a personal-best throw of 48-4.75/14.75m. That would rank among the school's all-time top 10 if she had not redshirted the 2013 season.
A number of Oregon alums had outstanding performances on Thursday.
Rupp bided his time before taking charge of the men's 10,000 meters to win the U.S. title going away. He won the gold medal in 28:37.42. Fellow alum Luke Puskedra placed ninth in 29:27.28.
Hasay ran a strong race in winning the silver medal in the women's 10,000 meters. She was in the top five from the outset, and outlasted everyone but eventual champion Shalane Flanagan, who left the field behind in winning in 31:43.20.Hasay, working with her new teammate Tara Erdmann for most of the race, first picked off Kara Goucher just over halfway through the race and then dropped Amy Hastings just into the last mile.
Hasay, a 2013 graduate, pulled away from Erdmann on the last lap to take the silver in 32:17.34.
"This is only the beginning," said Hasay of her first professional race. "It was great to go out strong for the first time."
Matthew Centrowitz won his 1,500 meter heat in 3:40.91 to automatically advance to Saturday's final. Andrew Wheating was right behind him in third, running 3:41.14 to also make the final.
English Gardner, the 2013 NCAA 100 meter champion who just turned pro, was second in her preliminary heat in 11.47 to advance to Friday's semifinal.
"I made it through, that's all I can ask for," said Gardner. "The middle was a little shaky, got carried by the wind a little bit. I was blowing like a kite out there."
Fellow alum Mandy White continued her strong season in the 100. She was fifth in her heat in 11.44, but advanced to the semifinal based on time.
Keshia Baker was second in her 400 meter opening round race and fourth overall in 51.72 as she advanced to Friday's semifinal.