BEIJING, China (AP) — Usain Bolt and Justin Gatlin set up the sequel to their world championship sprint showdown on Wednesday, both winning their semi-final heats in the 200 metres.

After Bolt edged the American by .01 second in Sunday’s 100m final, he will be seeking his record 10th world title overall on Thursday at the Bird’s Nest.

“I’m looking forward to it,” Bolt said. “This is my favourite event.”

Bolt was grinning widely after crossing in 19.95 seconds, coasting for about 60 metres and checking the stadium screens high up in the stands to see if someone could come close. As usual, none did.

“You save as much energy as possible, because you’re going to need it,” Bolt said.

In the previous semi-final heat, Gatlin, unbeaten over two years in the 200m, ran 19.87 seconds but worked a little longer than Bolt before easing up.

The two topped the qualifying times, with no one else breaking the 20-second barrier.

On a night when javelin thrower Julius Yego and steeplechaser Hyvin Kiyeng Jepkemoi extended the surprising lead of the Kenyans in the medals table to six gold, two of their teammates were provisionally suspended following initial positive doping tests.

The IAAF said it targeted Joyce Zakary, a 400-metre runner, and hurdler Koki Manunga for testing after competing in Beijing. Zakary ran a national record in the women’s 400 but the 29-year-old Kenyan did not start in the semi-finals. Manunga failed to reach the semi-finals in the women’s 400 hurdles.

Jepkemoi won a three-way sprint to the line to take the gold medal in the 3,000-metre steeplechase ahead of Habiba Ghibri of Tunesia and Gesa Krause of Germany. After a tight last lap, all three finished within .14 seconds of each other.

On the field, Yego set the best javelin mark in 14 years with a throw of 92.72 metres, good enough for an African record on top of gold.

In the most competitive final in history with five throwers surpassing 87 metres, Ihab Abdelrahman El Sayed of Egypt took silver with a throw of 88.99 and 2007 world champion Tero Pitkamaki of Finland took bronze with 87.64.

The 400m final also had its superlatives. Wayde van Niekerk blasted out of the blocks and never looked back to finish in 43.48 seconds and become the fourth best performer of all time. He was later taken away on a stretcher.

Behind him, LaShawn Merritt, the defending champion and 2008 Olympic champion, set a personal best of 43.65 but it still was only good enough for silver. Kirani James of Grenada took bronze.

With Yarisley Silva of Cuba clearing 4.90 metres to win the pole vault ahead of Fabiana Murer of Brazil and Nikoleta Kyriakopoulou of Greece, the Americans were locked out of a medal. Jenn Suhr, the Olympic champion, and Sandi Morris finished in a share of fourth place after failing to clear 4.80.

And Zuzana Hejnova of the Czech Republic kept the United States from gold in the 400 hurdles. Shamier Little of the United States got silver behind Hejnova, edging teammate Cassandra Tate.

In the medal standings, Kenya leads with six gold and 11 overall halfway through the championships, while the United States is back in fifth with one gold and nine overall.