DOHA, Qatar (AFP) - Kenya's world and Olympic 800m champion David Rudisha was one of 11 athletes to register season-best performances as the Diamond League opened in Doha on Friday.
Rudisha won in 1min 43.87sec with Ethiopia's Mohammed Aman, the only man to have beaten the Kenyan in the last three years, taking second in 1:44.21.
The Kenyan broke his own world record at the London Olympics last summer with a time of 1:40.91.
"It's a season-best, but I can do better in the coming weeks," said Rudisha.
In the men's 100m, America's 2004 Olympic champion Justin Gatlin won in Doha for the second successive year.
The 31-year-old, whose career was interrupted by a four-year doping ban, timed 9.97sec to beat fellow American Michael Rodgers with Jamaica's Nesta Collins in third, both men 0.02sec behind.
However, the 100m field was missing Olympic champion and world record holder Usain Bolt as well as world champion Yohan Blake.
"I have had a cold these last few days, but I am happy with this time at the start of the season," said Gatlin, who was the bronze medallist at the London Olympics.
Elsewhere, America's Dawn Harper-Nelson, the 2008 Olympic 100m hurdles gold medallist and silver medallist in London last year, improved her season's best to 12.60sec.
Harper-Nelson, who had run 12.62sec in Jamaica last weekend, finished ahead of compatriots Kellie Wells (12.73) and Queen Harrison (12.74).
Ethiopia's Hagos Grhhiwet, who has only just turned 19, celebrated his birthday in style by winning the 3,000m.
The world cross-country champion won in a time of 7min 30.36sec to hammer home his status as the natural heir to four-time Olympic champion Kenenisa Bekele.
Allyson Felix, who collected triple gold -- 200m, 4x100m and 4x400m -- in London, was defeated in the 200m by world champion Amantle Montsho of Botswana.
Other Olympic champions taking victories on Friday were Croatia's Sandra Perkovic in the discus, thanks to a throw of 68.23m and America's Christian Taylor with a 17.25m leap in the triple jump.
Former basketball player Brittney Reese, the Olympic gold medallist in the long jump, won with 7.25m.
Reese, also the world champion, finished ahead of Nigeria's Blessing Okagbare (7.14m) and America's Janay DeLoach (7.08m).