LONDON (AP) — Wayde van Niekerk’s biggest rival in the 200 meters never even made the start line.

Isaac Makwala was supposed to run in Heat 5 of the first round at the world championships on Monday, but the Botswanan’s spot in Lane 7 remained empty.

The IAAF later said Makwala withdrew “due to a medical condition on the instruction of the IAAF medical delegate.”

If Makwala had no medical reason to withdraw, he would have been ineligible to compete in Tuesday’s 400 final.

It was unclear whether Makwala’s no-show would extend to Tuesday’s final of the 400, where he and Van Niekerk are favored to go head-to-head for gold.

Van Kiekerk had earlier done his part in the third heat of the 200, keeping his quest for the 200-400 double going. And he spent as little effort as possible.

The South African even seemed ready to do British runner Daniel Talbot a favor by handing him a victory. He eased at the line and twice looked at the hard-charging Talbot, but Van Niekerk still ended up crossing the line .001 seconds in front.

Both Van Niekerk and Talbot were timed at 20.16 seconds.

Van Niekerk was smiling as he crossed the line, again showing the great form he is in at the championships. As defending champion, Olympic champion and world-record holder, Van Niekerk is favored to get his first gold of this year’s worlds in the 400.

In the first final on Monday, Anita Wlodarczyk of Poland left it late but won her third world title with one massive hammer throw.

Wlodarczyk, the dominating figure over the past half-decade with two Olympic gold medals, took the lead on her fourth of six attempts and then had her winning throw of 77.90 meters on her penultimate attempt.

Early leader Wang Zheng of China took silver with a throw of 75.98 meters and another Pole, Malwina Kopron, won bronze with a toss of 74.76.

Another multiple champion showing great form was Christian Taylor. The American needed only one attempt to show he is still the man to beat in the triple jump.

With the automatic qualifying standard set at 17 meters, Taylor hit 17.15 right away and reached Thursday’s final.

Taylor already has two world titles and two Olympic gold medals.

Another American, Chris Benard, also immediately qualified for the final with a mark of 17.20, while 18-year-old Cuban Cristian Napoles jumped 17.06.

Aries Merritt will be looking to get a second gold later Monday at the Olympic Stadium, five years after he won the 110-meter hurdles at the London Games.

Since the 2012 Olympics, Merritt has had a kidney transplant. But the world-record holder is back near his best at this year’s world championships.

He will face Olympic champion Omar McLeod of Jamaica and defending champion Sergey Shubenkov of Russia.

Other finals Monday are the women’s hammer throw 1,500 meters and triple jump.

___

More AP track coverage: https://www.apnews.com/tag/London2017