Shaun Murphy comes from behind to beat Ding Junhui
Defending World Grand Prix champion Shaun Murphy came from two frames down against Ding Junhui to advance to the quarter-finals.
Ding got off to a terrific start with breaks of 57 and 60 to take the opening two frames with Murphy making some uncharacteristic errors.
Murphy, who looked trouble by an irritation in his left eye following a contact lens issue, bounced back with two half-centuries of his own with breaks of 75 and 84.
Ding re-took the lead with an 81 before Murphy notched 68 to draw level again.
Last year's winner triumphed thanks to his fourth half-century of the game and he will now face Ryan Day in the next round.
Ryan Day beat fellow Welshman Michael White 4-2 but he will be gutted that he missed a glorious chance for a 147, only to leave himself with too difficult a shot on the pink.
Mark King took a 2-0 lead against Ali Carter only to see 'The Captain' come back to make it 2-2.
The pair produced just one half-century between them, King's 63 in the second, and it was the Northern Irish Open champion who made it through to the next round with a narrow 48-45 win in the final frame.
King will face in-form Marco Fu in the last eight after the Scottish Open winner enjoyed a 4-2 success against Anthony McGill.
Last 16 draw/results
Ali Carter 3-4 Mark King
Anthony McGill 2-4 Marco Fu
Michael White 2-4 Ryan Day
Shaun Murphy 4-3 Ding Junhui
Martin Gould v Joe Perry
Mark Allen v Liang Wenbo
Ronnie O'Sullivan v Neil Robertson
Barry Hawkins v Judd Trump
First round results
Mark Selby (1) 3-4 Martin Gould (32)
Joe Perry (16) 4-2 Mark Williams (17)
Anthony Hamilton (9) 0-4 Mark Allen (24)
Liang Wenbo (8) 4-0 Dominic Dale (25)
Ronnie O'Sullivan (5) 4-2 Yan Bingtao (28)
Neil Robertson (12) 4-2 Ricky Walden (21)
Barry Hawkins (13) 4-2 Kyren Wilson (20)
Judd Trump (4) 4-2 Tom Ford (29)
Ali Carter (3) 4-3 Zhou Yuelong (30)
Mark King (14) 4-3 Stephen Maguire (19)
Anthony McGill (11) 4-1 David Gilbert (22)
Marco Fu (6) 4-2 Jamie Jones (27)
John Higgins (7) 3-4 Michael White (26)
Stuart Bingham (10) 2-4 Ryan Day (23)
Shaun Murphy (15) 4-1 Michael Holt (18)
Ding Junhui (2) 4-2 Yu Delu (31)