Last season's Crucible finalist Peter Ebdon made a surprise exit at the Northern Ireland Trophy in Belfast on Tuesday afternoon.
Peter Ebdon was a second round loser at the Waterfront Hall
Ebdon was beaten 5-3 by Welshman Dominic Dale in the second round clash at the Waterfront Hall.
Ronnie O'Sullivan had to battle all the way before securing a 5-4 victory over England's Stuart Pettman.
Current Masters and Grand Prix champion John Higgins is through after a 5-3 win over Robert Milkins.
Matthew Stevens had no problem against Mark King, winning 5-0, while Mark Williams was almost as dominant against Andrew Norman, claiming a 5-1 success.
World champion Graeme Dott defeated Jamie Burnett 5-3 earlier while Ryan Day hammered Barry Hawkins 5-1.
Dott had to battle back from 3-2 down to claim a third round meeting with Mark Selby who beat Ali Carter 5-2 on Tuesday morning.
Dott, helped by an 80 break, led 2-0 but he then had to respond after Burnett claimed three frames in a row.
A fluked red in the final frame of the match helped Dott progress to the third round.
The world number six said after the success: "It's important to win your first match of the season, especially after winning the world title.
"If you win things can happen quite quickly and infest. You want to get that first win under your belt."
Wellingborough potter Ebdon, the world No 7 and 2002 world champion, knocked in breaks of 128, 61 and 60.
But Dale was also in top form and, with runs of 104, 62, 59, 56, 52 and 45 securing his path into the last 16.
"Beating Peter is a big scalp for me, but I feel I'm back playing at a level I'm happy with," revealed Dale, who has been working hard on his technique during the summer.