Usain Bolt won his first-round heat in the 100-meter dash, but to him it didn’t feel like a victory. (Kai Pfaffenbach/Reuters)

To the average viewer, Usain Bolt appeared to run a pretty good race Friday, when he competed in what is scheduled to be his final IAAF World Championships before he retires from track and field this month.

The 30-year-old cruised to victory in his preliminary heat of the 100-meter sprint in 10.07 seconds, but afterward said he did “very bad.”

“I stumbled a little bit, coming out my blocks,” he told the BBC (via Yahoo Sports) from the London event. “I’m not really fond of these blocks. I think these are the worst blocks I’ve ever experienced and it was just not a smooth start.”

The eight-time Olympic gold medalist added: “I have to get this together. I have to get started because I can’t keep doing this.” Bolt also complained that the blocks felt “shaky.”

“When I did my warm-up and pushed back, [the starting block] fell back,” he said. “It’s just not what I’m used to.”

The IAAF has not commented on the starting blocks. Bolt appears to be the only runner so far to publicly complain about them.

Bolt, who holds the world record in the 100-meter dash at 9.58 seconds, will race again on Saturday, first in the 100-meter sprint semifinals and, if all goes as planned, in the final. If he wins, the Jamaican will earn his fourth gold medal in the event at worlds.

Bolt will face stiff competition, not least of which comes from fellow Jamaican Julian Forte, the only man to break the 10-second mark during Friday’s preliminaries. He finished the race in 9.99 seconds in the third heat of the day.

In total, eight men either bested or tied Bolt’s time of 10.07 seconds in the prelims on Friday, including Team USA’s Justin Gatlin, who won his heat in 10.05 seconds.

Unlike Bolt, a crowd favorite, Gatlin was booed on the track, something he’s endured since failing a drug test more than 10 years ago. Bolt, however, does not count himself among one of the jeering masses.

“I personally think he’s a great athlete,” Bolt told the Jamaica Observer after last summer’s Olympics in Rio de Janeiro. “He shows up and pushes you to run fast and be at your best at all times.”

Gatlin and Bolt are set to run in different heats during Saturday’s semifinals. Both are expected to qualify for the final later that night.

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