China's Zhou Yuelong stunned world number six Mark Allen 10-7 to reach the second round (last 16) of the world snooker championship on Wednesday.
The 21-year-old Zhou, ranked 33rd in the world, took a 7-2 lead overnight and extended his advantage to 9-2 after the competition resumed in the afternoon.
Northern Ireland's Allen, who has won the Masters, the International Championship and the Scottish Open crowns this season, recovered to win five frames in a row to make it 9-7.
Zhou, competing at Crucible for the second time, finally took the 17th frame for the most important victory of his career. He will next face Jack Lisowski or Ali Carter.
Allen, 33, has suffered the opening round defeat at the Crucible for the first time since 2013.
"I'm happy to win," said Zhou. "Mark played very well from 9-2, he scored fast and heavily. I just had to wait for my chance and concentrate on every shot.
"I think this was my best match of the season, especially yesterday's session. I'm excited for the next match. I was happy to play against Mark, he's one of the best players in the world. I enjoyed it.
"In snooker you just have to do your own job, concentrate on yourself. If you think about your opponent too much it has a bad effect on your own game. I just focus on myself."
Zhou, who lost to fellow Chinese Ding Junhui two years ago, said that experience has helped a lot in his preparation for the match.
"The experience two years ago was very precious for me," he said. "Everybody is nervous when he plays at Crucible for the first time. But this time I just focused on my own game."
Allen said: "The way I played in the first 11 frames, I didn't deserve to win a match - it was embarrassing. I prepared really well for the tournament and I was hitting the ball great leading up to it, but just went out there and played like terribly.
"I really fancied the job from 9-6. I'm disappointed with the way it ended with a bad safety on the red in the last frame because I felt like I had him on the ropes. I'm proud of the way I hung on even though I was no where near my best."
China's Li Hang competes during the first round first session with England's Barry Hawkins at the World Snooker Championship 2019 in Sheffield, Britain on April 24, 2019. (Xinhua/Craig Brough)
Li Hang, the last Chinese player to appear at Crucible this year, was crushed by Barry Hawkins 10-1.
World 28th-ranked Li, 28, narrowly avoided the same fate of compatriot and fellow debutant Luo Honghao, who became only the second player to suffer a whitewash at the Crucible in losing 10-0 to Shaun Murphy.
Li's exit means that only two out of six Chinese players, Ding and Zhou, reached the second round.