US sprinter Noah Lyles "clenched" his way to 200m victory in 19.74 seconds in the Brussels Diamond League final on Friday to underline his medal credentials at the world championships that start later this month in Doha.
The 22-year-old went to last week's first final in Zurich and pipped American teammate and current world champion Justin Gatlin to win the 100m.
Lyles, however, will only race the 200m at the September 27-October 6 world championships in Doha.
The American went into the 200m in the Belgian capital as hot favourite, having clocked 19.50sec in Lausanne last month, a time that made him the fourth fastest of all time over the half-lap race, followed up by a meeting record of 19.65 in Paris.
But Lyles revealed a last-minute need for the toilet almost scuppered his run.
The track at Brussels' King Baudouin stadium is a rapid one, and Lyles opted for the relatively wide lane seven, outside Canadian Andre de Grasse and inside Trinidad and Tobago's Jereem Richards.
He made no mistake, hitting the bend ahead of Richards and opening up down the home stretch, only to find world and European champion Ramil Guliyev of Turkey pushing him all the way to the line.
Guliyev came in second in 19.86sec, just one-hundredth ahead of De Grasse.
"It started raining there, but you've got to be a pro and run in all conditions," said Lyles, who said the race had been "chaotic".
"A lot happened in that race! I get on the line and as soon as the starter says get to the blocks, it started raining. Then my bib comes off and then I had to use the bathroom and that's when the race became a lot more complicated," he said.
"I didn't get to experience the Brussels bend as I wanted to. It was more me clenching, trying to run and then using the bathroom.
"It's the first time it's ever happened to me. Normally I do everything before the race and I did that today. You can't control nature, I guess."
- 'Not a bad thing' -
Lyles tried to look at his uncomfortable experience as "not a bad thing".
"It proves I can handle all conditions," he said. "This was definitely a test to see if I could do that!"
His time of 19.74sec was a way off the meet record of 19.26sec set in 2011 by Jamaican Yohan Blake.
Blake's time remains the second fastest time ever run over the 200m after Usain Bolt's world record of 19.19sec set in the 2009 Berlin world championships.
American Walter Dix ran 19.53sec behind Blake in 2011 and Bolt himself has clocked a 19.57sec at the stadium, where there have been an impressive 26 sub-20sec performances in the 200m.