Ken Doherty delighted to end barren spell by beating John Higgins in Wales
World number five Higgins had been in fine form on Monday at the Newport Centre, beating Gareth Allen 4-1 with breaks of 120, 99 and 97, but could not replicate that display against his fellow former world champion.
Doherty took the first two frames but Higgins won a tense third, clearing from the green to settle a low-scoring and closely-fought frame.
Doherty needed several attempts to wrap up the next frame, but finally did so by potting the final brown to move within one frame of victory.
A break of 46 put him in control in the next and Higgins' response stalled at 14 before the Irishman sealed victory.
"It was a war of attrition, there was a lot of good safety. You have to match John in every department and I beat him with my safety game today," the 43 year old Dubliner said.
"I have been starved of winning matches against the top players so it's a great result for me. I'm in the twilight of my career but there's still a bit of sparkle.
"It's like a rare fruit that you find now and then and it still tastes sweet. It gives me a real boost of confidence. People think I'm just a pundit now so it's nice to show I can still play."
In the last 16 Doherty next faces the winner of Ricky Walden's match with Tom Ford.
"I have played Anthony a few times this season and he has beaten me," said the Scot.
"He's a great player and he was scoring heavily at the start. It was a good match for the first four frames and then we both struggled."
Sam Baird made short work of an upset win over Northern Ireland's Gerard Greene, a break of 73 wrapping up a 4-0 win for the world number 89.