Eighteen-year-old Abdul Hakim Sani Brown twice clocked 10.06 seconds at the national athletics championships Friday to reach the men's 100-meter final with the fastest time.

On the first day of the meet which doubles as a qualifier for the world championships in August in London, Sani Brown reproduced his time from the heats in the evening semifinals to book one of eight lanes in Saturday's final at Yanmar Stadium.

Sani Brown's time was the sixth fastest 100 ever run by a Japanese and met the world championships qualifying standard of 10.12. He took 0.12 off his previous best, holding off another rising star in Shuhei Tada (10.10) and Rio Olympic 4x100 silver medalist Ryota Yamagata (10.31) in the second semifinal.

The race's defending champion, Asuka Cambridge, came from behind to win the first semi in 10.10 over Yoshihide Kiryu (10.14) to secure his passage to the final, where the contestants will be trying to become the first Japanese to break the 10-second barrier. The top three finalists qualify for the Aug. 4-13 worlds.

Sani Brown, who is also entered in the 200 heats Saturday, took himself by surprise with Friday's results.

"I'm a bit shocked myself," the University of Florida-bound teenager said.

"In the prelims, I crouched too low at the start and in the semifinal, it took a while for the gun to go off after I was set, so I wasn't completely happy with the performance. We'll see how my body responds tomorrow after running the 200."

"I've been putting in the work so it's been worth it. I wasn't expecting to put up such good times like this."

But Sani Brown was not ready to celebrate yet. "It doesn't mean anything if I'm first in the semifinal but don't win the final. It's going to be an incredibly competitive race tomorrow. I'm looking forward to it."

Cambridge, unlike his Rio teammate Yamagata who was fourth in the semifinal to barely advance, seemed loose and confident for what has shaped up to be arguably the most competitive 100 final in the meet's history.

"I feel pretty good and my times have been decent. I've been shaping up well for the nationals and I can't wait for the race tomorrow," Cambridge said. "Nine seconds would be nice, but the most important thing is to make the team for the worlds. We've got a really strong field."

In the men's 10,000, Suguru Osako, third at this year's Boston Marathon, defended his title with a 28:35.47 victory and will look to cap the 5,000-10,000 double on Sunday for the second successive championships.

Seito Yamamoto topped the pole vault by clearing 5.60 meters to make the worlds team. Ryota Kashimura won the hammer throw with an effort of 71.36 meters.

Mizuki Matsuda won the women's 10,000 in 31:39.41 to punch her first ticket to the worlds, while Hitomi Katsuyama won the hammer throw by reaching 63.32 meters with Haruka Nakano capturing the high jump with a leap of 1.80. Ayaka Kora finished first in the long jump (6.14).