Only the Olympic champion, Canada's Donovan Bailey, who set the world record of 9.84 at the 1996 Atlanta Games, and the American Leroy Burrell, who set the previous world mark of 9.85 in Lausanne four years ago, have run faster.
Boldon, who also clocked 9.86 at a meeting in Walnut, California, two months ago, finished 0.07sec ahead of Namibia's Frankie Fredericks. Boldon has vowed to reduce the world record to under 9.8 this year.
Colin Jackson, Britain's world 110m hurdles record holder, clocked 10.31 in the 100m and won his speciality event in 13.15. Jackson will run in both events at the European Cup final in St Petersburg later this month, when Britain's men's squad will be defending the title they won last year in Munich.