Usain Bolt used his strong finish to win the 100 meters in 9.98 seconds at the Golden Spike meet on Friday.
Bolt recovered from a slow start but pulled ahead in the second half of the race to breeze unchallenged to the victory.
With the time, Bolt improved on his season's best of 10.05 in the Cayman Islands on Saturday. After that first race of the season, he needed treatment on a tight hamstring in Germany on the way to the Czech Republic.
He didn't appear to be limited on Friday though his time was still far from his world record of 9.58 in 2009.
"My reaction was good," Bolt said about the start. "The power behind the start wasn't there. I didn't execute."
Ahead of the race, he said he would be happy with a time of 9.8.
"I had to get to work a little bit harder at the end to get up the speed," Bolt said. "If I can improve that it should be OK."
Bolt is also scheduled to race in the London Diamond League meet on July 22 in his only other competition in Europe, two weeks before the Rio de Janeiro Games.
"This is a very important season. This is a very big year for me," he added.
"I have a lot work to do. I just need to continue, need more races to go."
Ramon Gittens of Barbados finished second in 10.21 while Hassan Taftian of Iran was third in 10.25.
It was the eighth time Bolt has raced at the Golden Spike. In 2012, he won the 100 in Ostrava in 10.04, a poor time by his standards, before he won three more gold medals at the London Olympics. He won his first three golds at the 2008 Beijing Games.
Olympic champion Renaud Lavillenie of France cleared 5.83 meters to win the pole vault, beating world champion Shawnacy Barber of Canada, who made 5.70.
Jarret Eaton led the American 1-2 finish in the 110 hurdles, in a personal-best 13.25 seconds to edge Jeff Porter by 0.17.
World and Olympic decathlon champion Ashton Eaton of the United States, who was scheduled to compete in the long jump and later in the 100 alongside Bolt, withdrew from the his first competition after completing only two jumps.
"During the second jump, I felt something happened in my left quad," Eaton said. "I don't know what happened but I don't want to take a risk in the Olympic season."
Paralympic long jump champion Markus Rehm of Germany had the best leap of 8.13. The rest of the field was placed in a separate category with Radek Juska of the Czech Republic taking the competition with a jump of 7.92.
Rehm hopes to become the second athlete with a carbon-fiber prosthesis to compete in the Olympics and the Paralympics after Oscar Pistorius in 2012.
"I hope I can perform at the Olympics but it will be the issue in next weeks," he said.
Thomas Roehler of Germany dominated the javelin with a world-leading throw of 87.37 meters.
In the 200, Briton James Elligton won in a tight finish in 20.35 seconds, edging Likourgos-Stefa Tsakonas of Greece by 0.01. Also, Javon Francis of Jamaica won the 400 in 44.87, while LJ Van Zyl of South Africa was the fastest in the 400 hurdles in 48.67.
Christine Day of Jamaica took the women's 400 in 51.09, well ahead of Carline Muir of Canada who clocked 51.84 while Jessica Beard of the United States had 51.88 in third.
World 400 hurdles champion Zuzana Hejnova of the Czech Republic finished third in her first race of the season, clocking 55.69 in a race won by Joanna Linkiewicz of Poland in 55.40.
Another world champion, Yarisley Silva of Cuba, was also beaten in her season debut by Czech Jirina Ptacnikova who cleared 4.60 meters in the pole vault.