World champion Kyren Wilson suffered a last-16 exit at the Scottish Open after he lost 4-1 to Chang Bingyu.
Mark Allen could have gone the same way, but he held his nerve to secure a 4-3 success over Zhang Anda.
Mark Selby had no such trouble after he whitewashed Noppon Saengkham.
Two matches went beyond midnight at Meadowbank Centre in Edinburgh, with Zhou Yuelong able to fight back from two frames down to edge out Stuart Bingham in a decider after a superb break of 133.
Joe O'Connor had to wait a little while longer before he beat Zak Surety by a 4-2 score to progress into the quarter-finals.
