Eugene (United States), July 1 (IANS): Top American sprinters Justin Gatlin and Tyson Gay are not prepared to write off Usain Bolt just yet as they conspire to dethrone him at the Beijing World Championships in August.

Bolt, who qualifies for the 100 metres and 200 metres at the World Championships automatically as the defending champion in both events, has struggled for form this season. But both Gatlin and Gay are convinced the Jamaican superstar will be at his best when it matters, that is August 22-30 in the Chinese capital, reports CMC.

"You never know until you cross the finish line. Everybody's going to be ready and prepared," Gatlin said.

Bolt, the 100m and 200m world record holder, has only managed best times of 10.12 seconds and 20.13 seconds over the two distances this year. His decision not to compete at the just concluded Jamaican National Championships has also served to heighten concerns about his fitness level.

He also pulled out of the Pairs and Lausanne Diamond League meetings on Tuesday. However, Gay said the best approach was to prepare to face Bolt at his best.

"Right now I'm not paying attention to Usain Bolt. He's a championship performer. He'll be ready when it counts," Gay said.

Gatlin holds the top time in the world this year in 100m with 9.74 seconds while Gay has clocked 9.87 seconds. Bolt, however, has yet to break 10 seconds in 100m in 2015 or 20 seconds in 200m.

Gatlin and Gay will lead a strong US sprint contingent to the World Championships, aiming to wrest the coveted 100m crown from Jamaica's grasp. The once-dominant Americans have not won a global 100m title since 2007 when Gay won both the 100m and 200m world titles.