Kenyan Silas Kiplagat shocked compatriot Asbel Kiprop to become the fourth-fastest 1,500 meters runner of all time at a sizzling Monaco Diamond League meeting on Friday.
Kiplagat broke through to run a year-leading three minutes, 27.64 seconds and surprise two-time world champion Kiprop, who was attempting to break Hicham El Guerrouj's 16-year-old world record of 3:26.00 in the race.
"I could see Silas coming closer and closer. It was a tough race," said Kiprop, who ran 3:28.45.
Kiplagat said he too would be thinking about the world record in the future.
"I have the fast time now, but why not be faster and attack the world record?" he told reporters.
"I always run well here, so I'm thinking my win and result is no surprise. I was aware I can do it."
Botswana's Nijel Amos and U.S. sprinters Justin Gatlin and Tori Bowie also posted the best performances of the year.
Olympic silver medallist Amos delivered a second middle-distance surprise when he defeated fading Kenyan world record holder and Olympic champion David Rudisha in the 800 meters.
Amos finished in 1:42.45, the year's top time, with Pierre-Ambroise Bosse setting a French record of 1:42.53 in second place. Rudisha was fifth.
Gatlin continued his unbeaten sprint season by running a personal best in the 200 meters with 19.68 seconds. Only seven men have run faster.
Gatlin already was the year's leader at 100 meters.
"I'm ready to face the best Jamaicans in both sprints," the 32-year-old Gatlin said. "This year I want to win the Diamond Race in the 100m and stay unbeaten."
Jamaican Nickel Ashmeade was his closest challenger at 19.99 seconds with France's Christophe Lemaitre third and American Tyson Gay fourth.
Bowie overwhelmed a world-class field in the women's 100, clocking 10.80 seconds as she easily defeated Jamaican Veronica Campbell-Brown, who finished in 10.96.
Ukrainian world champion Bohdan Bondarenko continued an outstanding season for high jumpers, clearing 2.40 meters to outlast indoor gold medallist Mutaz Essa Barshim of Qatar.
Another world champion, Colombia's Caterine Ibarguen used her last attempt in the women's triple jump to bound 15.31 meters and become the fifth-best ever in the event.
(Reporting by Gene Cherry in Raleigh, North Carolina; Editing by Greg Stutchbury)