Kenya's Beatrice Chebet smashed the women's 5,000 metres world record and compatriot Faith Kipyegon broke her own 1,500m record again as the Eugene Diamond League meet lived up to its billing on Saturday.
Olympic champion Chebet ran 13 minutes 58.06 secondsto better the time set by Gudaf Tsegay by over two seconds, the Ethiopian's 14:00.21 obliterated when the Kenyan left Tsegay for dust with 200 metres to go as she sprinted for the line.
Chebet looked in shock when she saw the time, adding to her world 10,000 metres record set in Eugene last year, but she had been threatening the record, running 14:03.69 in Rome last month.
"I'm so happy, after running in Rome, I said I have to prepare for a record, because in Rome I was just running to win a race, but after running 14:03, I said that I'm capable of running a world record," Chebet said.
"So, let me go back home, and then come to Eugene. When I was coming here to Eugene, I was coming to prepare to run a world record, and I said I have to try."
Tsegay, along with Kenyan Agnes Jebet Ngetich, kept pace with Chebet for almost the entire race, but had no answer when Chebet kicked for home, and Jebet Ngetich finished second in 14:01.29, the third fastest time ever.
The 50th Prefontaine Classic promised fireworks, and in the final race of the evening Kipyegon ran a time of three minutes 48.68 seconds, improving her previous world mark of 3:49.04 set in Paris last July.
Kipyegon, triple Olympic champion over the distance, recently fell short in her attempt to become the first woman to run a mile in under four minutes, but the 31-year-old shook that disappointment off in style.
The Kenyan upped the pace down the back straight, powering around the final bend and pushed for the line, her eyes wide in disbelief as she glanced at the clock as she broke the tape.
Sweden's Mondo Duplantis failed in his bid to break his own world pole vault record for a 13th time.
Duplantis, who recorded his best jump of 6.28 metres in Stockholm in June, faced little competition, with nobody left at 5.90, and after clearing six metres he attempted 6.29 but was unsuccessful in all three attempts.
The men's 100m was dominated by Jamaican Olympic silver medallist Kishane Thompson, winning in a time of 9.85 seconds, one tenth of a second off his personal best set eight days ago, with Briton Zharnel Hughes in second.
"I'm the only one that can stop me," Thompson said. "I don't say that to brag, but to be honest, once I better my execution, amazing things are going to happen."
Olympic 400m metres hurdles champion and world record holder Sydney McLaughlin-Levrone took on the flat race at the same distance and held off a late surge from fellow-American Aaliyah Butler.
American Yared Nuguse looked like threatening the world mile record before a late collapse saw him caught before the line by Dutchman Niels Laros.
"I didn't get the record, but I'm still at a really good place right now," Nuguse said.