Maurice Greene backs Yohan Blake to beat Usain Bolt at London 2012

Usain Bolt and Yohan Blake
Blake (left) trains with fellow Jamaican Usain Bolt

Ex-world record holder Maurice Greene has backed 100m world champion Yohan Blake to beat reigning Olympic champion Usain Bolt in the 100m at London 2012.

Greene, who won Olympic 100m gold in 2000 in Sydney, argued that Jamaican Bolt has "trouble in close races."

Bolt was disqualified for a false start in August's World Championships, as Blake went on to win 100m gold.

"If everybody competes like they did this year, I'd say Yohan Blake is going to win," Greene told BBC Radio 5 live.

"He's the world champion so his confidence is getting higher and higher all the time.

"Remember they train together and the way it sounds to me, he [Blake] seems to be the dominant person in the 100m in their training group.

"So everyday they are training together, his confidence is getting bigger and bigger. When they come to the Games, if Usain is still having those problems, Blake's confidence level will be through the roof and he's going to be hard to handle.

"Usain has trouble in close races. If you think about the close races he's had, he's lost [them]."

Bolt, 25, has dominated the sprinting world in recent years and currently holds the world record in both the 100m and 200m.

He won the 100m and 200m sprint double in then-world record times at the 2008 Olympics in Beijing and then matched his feat the following year at the World Championships in Berlin, setting new marks of 9.58 seconds in the 100m and 19.19 in the 200m.

The Jamaican lost his world title to Blake in 2011 in Daegu, South Korea but recovered to retain his 200m title.

Blake, who won world 4x100m relay gold with Bolt in Daegu, has had the best year of his career in 2011, following up his maiden world title by beating countryman Asafa Powell in the 100m with a personal best of 9.82 in September.

A week later, he set the second fastest 200m time ever of 19.26.

Greene retired from sprinting in 2008 after a career which saw him win two Olympic golds and five world championship titles.

In 1999, he beat Donovan Bailey's 100m world record of 9.84 when he ran 9.79 in Athens, Greece.