Defending champion Kyren Wilson of England was ousted from the World Snooker Championship by China's debutant Lei Peifan 10-9 in the first round on Saturday.

33-year-old Wilson led 6-3 after the morning session in the opening match at the Crucible Theatre in Sheffield this year, but met strong challenges from Lei since the beginning of the evening session as the 21-year-old Chinese qualifier took six consecutive frames.

The world No. 2 fought back to force a 9-9 draw, but Lei kept his cool to seal the victory by winning the deciding frame 80-14.

"It feels amazing. The Scottish Open was my first title and this was my Crucible debut. Both moments are very special to me," said Lei, who won his first ranking title at the Scottish Open last December.

Wilson admitted it's really hard to take the defeat, but also said he has done so much in a long season.

The 39th-ranked Lei will face the winner between China's Zhao Xintong and Jak Jones of Wales.