British teenager Adam Gemili will line-up with Usain Bolt in the 200 metres final hopeful of winning a World Championship medal.
On a remarkable day in Moscow, the 19-year-old twice broke his personal best and became only the second Briton ever to break the 20-second barrier.
John Regis is the only Briton who has gone faster than Gemili, whose 19.98-second semi-final sprint saw him through to the final as the second fastest qualifier.
"I was in shock going over the line and seeing the time," Gemili said. "Looking around, I did not quite realise it was me that had run it until I looked up at the big screen.
"Training has been going well. I have missed quite a lot of the season, winter training and stuff through injury, so to run a time like that, put myself in the final amongst the quickest men of the world, I am over the moon.
"I was really shocked and it took me a while to compose myself. I just went out there and executed it. Luckily enough the time was great as well."
Gemili managed to take a staggering 0.32 secs off his previous best over the course of a 10-hour period, having headed to Russia with a PB of 20.30 and lowered it to 20.17 in the heats.
It raises the exciting prospect of what he might be capable of on Saturday.
"Every athlete comes here to put themselves in a final," Gemili said. "Anything can happen in a final, as we know from previous world champs.
"I am going to go out there and execute. If I go out there and run how I know I can run, then you never know.
"I don't see why I couldn't get a medal but that is not to be the main aim going in. The aim is just to go out and execute."
Gemili crossed the line in a faster time than Bolt, although it will take something miraculous for him to be beaten in the final.
Champion over 200m at the previous two Olympics and World Championships, the Jamaican went through in 20.12s after South Africa's Anaso Jobodwana pushed him close in a frantic end to a comfortable race.
"I am happy I qualified for the final," Bolt said. "I am looking forward to seeing how fast I can go tomorrow in the final. I want to defend my title.
"Today I was trying to slow down early, but then I saw Jobodwana on the inside. I didn't want to lose the race, so I had to switch gears for the last 25 metres.
"For the final I'd like to get an outside lane, it will be easier for me."
Countryman Warren Weir will likely prove Bolt's biggest rival on Saturday, although Curtis Mitchell looked impressive and qualified fastest with a PB of 19.97.
The American sprinter clocked that time in the first heat - a race which Great Britain's Delano Williams finished seventh.
The 19-year-old world junior champion from the Turks and Caicos Islands was drawn in the outside lane and was never in contention, coming home in 20.61.
It wasn't the best but I did my best and that's all I can ask for," Williams said.
"Right now I need to relax myself, watch the rest of the champs and see where best I can learn from them."
James Ellington was the other Brit in semi-final action at the Luzhniki, coming fourth in Bolt's race in 20.44.
"Having Usain Bolt coming up on the inside was a bit off-putting but there's nothing I can do about that, so you panic about it but with experience I'll learn not to do that in future races," he said.
"I think I had the capability of running 20.2 or faster which would have made the final. I had a good year, I've been consistent and I can build on it for the future."