World Championship debutant Michael Wasley caused the shock of the tournament so far by defeating world number two Ding Junhui.
The world number 75 won 10-9 to reach the second round after recording a break of 103 to force a deciding frame.
Ding held a 6-3 overnight lead at the Crucible Theatre but Wasley fought back to earn a match against either 13th seed Mark Davis or Dominic Dale.
Mark Selby defeated Michael White 10-9 and will face Ali Carter.
The world number three, bidding to reach his second final after losing to John Higgins in 2007, made breaks of 88 and 78 to open up an 8-5 lead before seeing off a White revival to take the final frame.
Ricky Walden, seeded 11th, opened up a 6-3 lead over fellow Englishman Kyren Wilson in a match that will resume at 19:00 BST on Tuesday.
England's Joe Perry progressed by winning six frames in a row to beat Jamie Burnett of Scotland 10-7.
Perry, a semi-finalist in 2008, was 6-3 down after the first session but launched a comeback to go 9-7 in front before taking the victory and will now face defending champion Ronnie O'Sullivan in the second round.
In an all-Scottish match, veteran Alan McManus opened up a 6-3 lead over four-time world champion John Higgins, with the pair to return at 10:00 on Tuesday.