Jamaican sprint star Usain Bolt won the 200m in 20.03 seconds in the Diamond League meeting in Stockholm.
Reigning 400m world champion LaShawn Merritt returned to the track after a 21-month ban for a positive drugs test, finishing second.
Jason Richardson stormed to a 110m hurdle victory ahead of world leader David Oliver, in 13.17 seconds.
A stunning run from Vivian Cheruiyot set a world-best time of 14 minutes, 20.87 seconds in the 5,000m.
Bolt left his opponents trailing in the 200m, his preferred distance, opening up a five-metre lead over second-placed Alonso Edwards (20.47), with compatriot Ainsley Waugh placed third (20.56).
"Technically it was not a good race because the curves here are a bit tight," said the world record holder.
"I was careful not to get injured before the World Championships. But generally, it was a good race despite the fact that I wanted a better time."
Merritt's time of 44.69 seconds was an impressive return to competition ahead of next month's World Championships in Daegu, South Korea, following a suspension for testing positive for an over-the-counter male-enhancement product.
The 25-year-old United States athlete measured his pace well round the bend to put himself in contention on the home straight.
Jamaican Jermaine Gonzales won the race in a season-best time of 44.69 seconds, whilst Christopher Brown of the Bahamas completed the podium places (44.79).
"My mum and my team believed in me and they'll keep believing in me," said Merritt.
"To run 44.6 seconds in my first race, I can't complain. I needed to get that one out. I'm keeping my focus on the World Championships."
The women's 100m played out as expected with 31-year-old Carmelita Jeter taking pole position in 11.15, in front of fellow US sprinter Marshevet Myers (11.21).
Richardson sent out a big warning shot ahead of August's World Championships in a blistering 110m hurdle triumph ahead of pre-race favourite David Oliver.
Richardson blasted out of the blocks to put Oliver under immediate pressure as he bolted to a winning time of 13.17 seconds.
Oliver, who still tops the Diamond League standings, raced to 13.28 after hitting many of the barriers.
On Richardson, BBC Sport commentator Stuart Storey said: "He's a beautiful hurdler with terrific rhythm. That trail leg is as good as any I've seen."
South Africa's world 800m champion Caster Semenya finished a disappointing eighth in Stockholm, with Kenia Sinclair of Jamaica running a season's best time of 1:58.21 to take victory.
"I felt heavy," said Semenya. "I didn't run the race I wanted to run but I kept on going. It's a little bit upsetting but I guess it wasn't my day. I need to go back and train."
Jamaican sprinter Kaliese Spencer was the clear winner in the women's 400m hurdles in 53.74 seconds, leaving world and Olympic champion Melanie Walker trailing in second.
Silas Kiplogat, who won the previous 1500m in the Diamond League meeting in Monaco last week, completed another commanding performance to win in 3:33.94.
Elsewhere, Russia's Ivan Ukhov came out on top of an entertaining high jump competition with world leader Jesse Williams, world record holder Yelena Isinbayeva won the women's pole vault in her first Diamond League appearance of the season and Australian Mitchell Watt took the men's long jump.