China's Si Jiahui edged out 2005 world champion Shaun Murphy 10-9 to win his first match at the Snooker World Championship in Sheffield on Thursday.
Si, 20, is the lowest ranked player in the tournament. The world No. 80 had to win three qualifying matches to face Murphy, who is the fourth seed and has clinched two titles in the past two months.
After leading in Wednesday's first session 5-4, Si kept his good form on Thursday to upset Murphy 10-9, reaching the last 16 of a ranking event for the fourth time in his career.
"I didn't really play to win, I just wanted to learn from him," Si was quoted by the World Snooker Tour website. "I would not be too dissatisfied with myself even if I'd lost tonight because I did perform well and I was so happy out there."
Si will face Robert Milkins on Saturday as Milkins knocked out Joe Perry 10-9 earlier on Thursday.
Four-time world champion Mark Selby saw off Matthew Selt 10-8 to set up a last-16 clash with Gary Wilson.
