Ross Fisher caused an upset on day two of the WGC - Dell Technologies Match Play as he sent World Number Four Hideki Matsuyama tumbling out at Austin Country Club.
The Englishman was fighting for his life in Group 4 after losing his opener on Wednesday but was three up after four holes and survived a late rally from one of the planet's in-form players to win 2 and 1.
Louis Oosthuizen can still advance from Group 4 despite a defeat to Jim Furyk, while in Group 12, Charl Schwartzel faces a winner-takes-all clash against Paul Casey.
In Group 13, Thomas Pieters will need to beat Bubba Watson on Friday if he is to have a chance of reaching the last 16.
Fisher put his approach to concession range on the first as Matsuyama found a bunker and when the Japanese needed a drop off the tee on the third and found a bunker off the tee on the par three fourth, the lead was three holes.
The Englishman returned the favour on the seventh as he failed to find the putting surface but he quickly bounced back, putting an approach to five feet on the ninth to be in control at the turn.
A bogey after finding the water on the 11th cut the gap and the 12th was halved in bogeys despite Fisher pounding a 423-yard drive.
The duo traded the 13th and 14th and while Matsuyama won the 15th, Fisher rolled in an 18-footer on the penultimate hole for victory.
"I felt like I played pretty solid," said Fisher. "I had the match in control all the way. Just a couple of silly mistakes.
I felt like I played pretty solid. I had the match in control all the way. Just a couple of silly mistakes - Ross Fisher
"Fortunately for me, Hideki has not been at his best this week, so it's just nice to take advantage of that.
"Tomorrow is going to be a tough day. Jim Furyk is a great match player. I've played him before and managed to scrape a couple of wins against him."
Oosthuizen was a 4 and 3 winner over Fisher on Wednesday but he went down 3 and 2 after a real battle with United States 2018 Ryder Cup Captain Furyk.
Furyk was three up after six holes but Oosthuizen dragged him back to all square after ten before the 2003 US Open champion won the next three holes, with the 15th and 16th traded.
Schwartzel was in dominant form in sealing his second win of the week, eliminating Joost Luiten after a 4 and 3 triumph.
You go through and you win every single match, you will end up winning this tournament. For me, it's going to be the case - Charl Schwartzel
A par was enough to win the first and while the Dutchman won the fourth, he bogeyed four of the next seven to put Schwartzel comfortably through.
"I suppose match play, this is what it's all about," he said. "You go through and you win every single match, you will end up winning this tournament. For me, it's going to be the case. There's no slipping through."
Casey was a one up winner over Byeong-hun An, who was eliminated.
Pieters made just two birdies in 17 holes to lose 3 and 1 to Jhonattan Vegas. In the other Group 13 clash, two-time Masters Tournament winner Watson was a 4 and 3 winner against fellow American Scott Piercy, who was eliminated.
In Group 5, Hideto Tanihara halved his match with Ryan Moore, while Jordan Spieth beat Yuta Ikeda 4 and 2.
