New York: Usain Bolt’s coach Glen Mills has backed the sprinting superstar to come good at this month’s World Championships in Beijing.

The 28-year-old Bolt will enter the August 22-30 showpiece at the Bird’s Nest with question marks over his form after a series of lacklustre performances in recent months, as per reports.

However, Mills said while Bolt had suffered several injury setbacks recently which had affected his preparation, he was the type of athlete who was always highly motivated for major championships.

“The last two years have been very challenging for both Usain and myself,” Mills said.

“Unfortunately, he has had a number of different injuries to overcome which have affected his training and the number of competitions he has been able to compete in. But Bolt is a champion who knows nothing but excellence when performing on the world stage.”

Bolt enters the World Championships as the defending champion in both 100 and 200 metres following his conquests in Moscow two years ago, but with a serious challenge expected from a resurgent American Justin Gatlin.

This year, Gatlin has produced the better form, posting world-leading times of 9.74 seconds in 100m in Doha back in May and 19.57 seconds in 200m at the US trials in Oregon the following month.

Bolt’s 100m best this year has been a 9.87, clocking under pressure in London last month. The injury issues last year and early this season have been a major problem but Mills said a few changes to his training regime had proven productive.

“We have been making a number of changes on the way he trains and have been getting results. However, I would have wanted him to have had more races,” said Mills.

Bolt is the finest sprinter in the history of the sport. He captured the sprint double at the 2008 Beijing Olympics and successfully defended the titles at the following Olympiad in London three years ago.

He also did the double at the 2009 Berlin World Championships and only a false start in 100m at the 2011 edition in Daegu prevented him from completed yet another double.