Usain Bolt made a significant step up from the heats, but was beaten by Christian Coleman as the duo qualified fastest for the men's 100 metre final at the IAAF World Championships.
Bolt complained about the starting blocks after labouring to victory in his opening race. Despite another lacklustre getaway on Saturday, he clocked 9.98 seconds to advance behind Coleman - the fastest man in the world in 2017 and the first person to beat the Jamaican in a world or Olympic semi-final.
Having safely negotiated the qualifying rounds, Bolt will now end his sensational individual career in the final later on Saturday, when he will attempt to win the 100m for a record-breaking fourth time.
Coleman can be expected to provide staunch competition in the showpiece, though, his 9.97secs the fastest time of the event so far.
The pair gazed at each other as they crossed the line - both easing up - separated by one hundredth of a second, knowing they are the leading contenders for glory.
Akani Simbine disappointed in the heats and qualified as one of the fastest losers, but he was vastly improved in the semi-finals and won the opening race in 10.02s.
The South African was too quick for Justin Gatlin, but the American edged out Ben Youssef Meite to secure a spot in the final.
Another person to step up from the heats was Yohan Blake, but the biggest cheers of his heat went to Great Britain's Reece Prescod after he produced a sensational finish to edge out Su Bingtian for second, much to the delight of the adoring home crowd.
Su qualified for the final as one of the fastest losers, with Jimmy Vicaut taking the last remaining spot.