Rome, July 11 (DPA) Tyson Gay sent a warning to Usain Bolt when the American clocked the fastest 100 metres time of the year, 9.77 seconds, at the Golden League series stop in Rome.

The three-time 2007 world champion Gay moved ahead of former world record holder Asafa Powell of Jamaica early in Friday's race as he equalled his personal best.

Powell clocked a season-best 9.88 seconds and compatriot Yohan Blake was third in 9.96 seconds.

Bolt, who got a golden world record treble at the Beijing Olympics, had led the 2009 list with 9.86 seconds until Friday. The Jamaican star Bolt was not competing at the Golden Gala in Rome.

The showdown between Gay and Bolt will take place at the Aug 15-23 world championships in Berlin, where Gay has 100m, 200m and 4x100m titles to defend against Bolt.

Gay is also ahead of Bolt in the year's 200m list, 19.58 seconds to Bolt's 19.59, but Bolt's time Tuesday in Switzerland came despite terrible weather conditions.

Jamaica got its revenge in the women's dash when Kerron Stewart clocked a world-leading 10.75 seconds from compatriot Olympic champion Shelly-Ann Fraser (10.91).

Stewart's victory kept her in the race for the Golden League jackpot of $1 million at the halfway mark of the six-meet series, along with Russian pole vaulter Yelena Isinbayeva, US 400m runner Sanya Richards and Ethiopian 5,000m ace Kenenisa Bekele.

The four have won in Berlin, Oslo and Rome, with the big prize going to athlete(s) who win their events in Paris, Zurich and Brussels as well.