LONDON -- China's debutant Si Jiahui reached the quarterfinals at the Snooker World Championship after beating Robert Milkins 13-7 in Sheffield on Monday.

Si, 20, led their second-round encounter 11-5 after the first two sessions and took two frames each with the 47-year-old Milkins on Monday to wrap it up 13-7.

"Since the qualifiers, I have felt peaceful and calm emotionally," said the world No. 80 Si, who had to win three qualifying matches so as to challenge world No. 4 Shaun Murphy in the first round.

After edging out 2005 champion Murphy 10-9 last Thursday, Si kept his good form and comfortably won his second match at the Crucible Theater.

"I treat it as if it's a minor event, like a daily practice, and I try to enjoy the Crucible," Si was quoted by the World Snooker Tour website.

Si will face Anthony McGill on Tuesday as the 32-year-old reached the quarterfinals at the worlds for the third time in four years by beating Jack Lisowski 13-8.

Mark Selby saw off Gary Wilson 13-7 to set up a clash with veteran John Higgins.