Barry Hawkins scored one of his best results of recent seasons as he beat world number one Mark Allen 5-3 to reach the quarter-finals of the Xi'an Grand Prix.
That result opens the door for Judd Trump to take over as world number one if he can reach the final this week.
August seems to be a fruitful month for Hawkins as he reached the final of the European Masters in 2022, won the same event last year, and is now enjoying a fine run this week.
World number 15 Hawkins took a 3-0 lead with a top break of 94. Allen recovered to 4-2 and was on for a 147 in frame seven until he missed a tricky penultimate red on 104. And he had chances for 4-4 but could't take one and Hawkins wrapped up the result.
"To beat the world number one is brilliant," said Londoner Hawkins, age 45. "I still feel I have more to give. It depends wherther I can stay dedicated to practice and doing the right things off the table. Hopefully I've got another tournament win in me."
Shanghai Masters champion Trump has won eight out of eight matches so far this season and has lost only two frames this week. He cruised to a 5-1 win over Crucible runner-up Jak Jones with top breaks of 51 and 52.
China's Xu Si reached the second ranking event quarter-final of his career - and first since the 2017 Indian Open - with a superb 5-4 win over Mark Williams. From 4-2 down, Xu won the last three frames with top breaks of 77 and 109.
"After losing the sixth frame, I felt a bit frustrated," said Xu. "I had a chance to level at 3-3, but suddenly I was 4-2 down, which dampened my spirits. I took a break to the rest room to adjust myself. I told myself to focus on safety then opportunities would come.
"In the deciding frame, I adjusted my mindset well, and I was quite confident at that point. Playing against Mark was actually quite relaxing, and I didn’t put too much weight on winning or losing. Reaching the quarter-finals has already exceeded my expectations."
China's 17-year-old Gong Chenzhi saw his run end with a 5-4 defeat against Matthew Selt. Gong was one ball from a 5-3 victory when he missed the final pink, playing with the rest, leading by 13 points. He later went in-off during a safety bout, and Selt potted an excellent pink to middle then added the black for 4-4, and went on to dominate the decider.
"I didn't play well today but I'm delighted to win because I've always had a poor record in China and this is my first quarter-final here," said Selt.
"I'm playing with a new cue this week, with a titanium ferrule. I only had 45 minutes practice with it before my first match. A few others like Mark Allen, John Higgins, Kyren Wilson and Jak Jones are playing with titanium so I wanted to try. It's going to take six to eight weeks to get used to it. But one thing it has given me is that I know I have to concentrate harder - and that has worked so far."