Mark Allen has missed out on the Northern Ireland Open quarter-finals after being edged out 4-3 by Alexander Ursenbacher in Belfast.
Swiss Ursenbacher took a 2-0 lead before Allen hit back to make it 2-2 and after another frame apiece, Ursenbacher's break of 69 was enough to see off the home favourite.
Shaun Murphy booked his last-eight spot with a 4-2 win over Barry Hawkins.
Defending champion Judd Trump beat Yan Bingtao 4-0 to reach the quarters.
Five-time world champion Ronnie O'Sullivan will face Murphy for a place in the semi-final after a commanding 4-1 victory over Yuan Sijun, which included a break of 127 in the second frame.
Mark Selby proved too strong for veteran Dubliner Ken Doherty as he completed a 4-1 victory while John Higgins beat Stephen Maguire by the same margin.
Allen edged out in ding-dong battle
Having breezed past Scott Donaldson with a 4-0 win in the third round earlier on Thursday, world number seven Allen was in fine form as he took on Ursenbacher at the Waterfront Hall.
However, the 23-year-old had not read the script as he managed breaks of 62 and 64 to take the opening two frames.
Allen responded emphatically with a break of 101 to make it 2-1 before taking the fourth frame to level matters.
Ursenbacher showed his own resilience, producing a break of 72 to get his nose in front once more. Allen's excellent break of 103 made it 3-3 but Ursenbacher held his nerve to take the decisive seventh frame.
"I don't have many complaints," said Allen.
"I battled back to get back 2-2 and then missed the red in the middle and he made a very good break off that. I made it 3-3 but I never really got a chance in the last.
"It's the best I've felt playing here - I've just been beaten by someone who was playing very well."
Former world champion Murphy continued his impressive form as he dispatched fellow Englishman Barry Hawkins 4-2.
Murphy stormed into a 3-1 lead but 2016 NI Open finalist Hawkins came back in the fifth with a spectacular break of 129. Murphy took the next frame to seal his place in Friday's quarters.
2017 runner-up Bingtao was no match for world number one Trump, who produced another clinical display and took another step towards defending the Alex Higgins trophy. Trump has not dropped a frame since the third frame of his second-round clash win over Zhang Ada.
Elsewhere, Joe Perry beat Robbie Williams 4-1, John Higgins survived a Stephen Maguire fightback to win 4-3, while Anthony Hamilton also overcame Kyren Wilson by the odd frame.
|Northern Ireland Open quarter-finals|
|Judd Trump||v||Anthony Hamilton|
|Joe Perry||v||Alexander Ursenbacher|
|Shaun Murphy||v||Ronnie O'Sullivan|
|Mark Selby||v||John Higgins|