Usain Bolt made to work for his place in World Championships 100m semi-finals

The Jamaican clocked in at 10.07secs after a slow start out of the blocks

Usain Bolt ended his race with a shake of the head (Getty)

Michael Johnson had said ahead of the 2017 World Athletics Championships that Usain Bolt was “more vulnerable” than ever as he bids to retain his title as ‘the fastest man on earth’.

On the big occasion here at the London Stadium, the American’s words proved worryingly prescient.

Clocking in at 10.07secs in Friday's heats, Bolt booked his place in Saturday’s semi-finals but made hard work of it in the process.

Animated and playful as ever before the race, the Jamaican ended his 100m sprint with a disappointed shake of the head that said it all.

It was a far from flawless performance that saw Bolt pushed all the way by the likes of Britain's James Dasaolu and Jimmy Vicaut of France, both of whom also qualified for the semis.

Indeed, the 30-year-old struggled out of the blocks and found himself positioned sixth as the mid-way mark approached.

It took until the closing stages of the race before Bolt pulled ahead of the pack to keep his hopes of a 12th World Championships gold on course.

Speaking after the race the Jamiacan appeared to blame the blocks for his performance.

"I stumbled a bit coming out of blocks, I'm not fond of these blocks," he told the BBC. "I have to get this together. It's shaky because when I did the warm up it [the blocks] pushed back.

"It's not what I am used to."

The Jamaican may have been presented as “forever fastest” in his media conference earlier this week, but if Friday’s race is anything to go by his dominance looks to be drawing to a close.

Meanwhile, it was an encouraging evening for Britain’s male sprinters. Reece Prescod, Chijindu Ujah and Dasaolu all progressed to Saturday’s semi-finals, running 10.03secs, 10.07secs and 10.13secs respectively.