This was a day to prove why sponsors and broadcasters prefer the WGC Match Play in group rather than straight knockout format. Had the latter rules applied, Dustin Johnson and Rory McIlroy would have exited Austin Country Club after 18 holes.

Johnson, the defending champion and world No 1, was the biggest casualty of day one as he slipped to a 3&1 defeat by Bernd Wiesberger. McIlroy’s defeat by Peter Uihlein, 2&1, also raised eyebrows given the Northern Irishman’s heroics when winning the Arnold Palmer Invitational on Sunday. In both cases it would be remiss not to recognise the performances of the winners. Wiesberger, a European Ryder Cup hopeful, and Uihlein both displayed nerveless touch in illustrious company.

“I still didn’t play great but somehow managed to get it done and I’m just happy with that,” said Wiesberger. “I thought it was the easiest game I could have; I’m the underdog playing with the defending champion.”

McIlroy admitted to being “a little flat”. While he remains part of the tournament equation, he must beat Brian Harman and Jhonattan Vegas if his Masters build-up is to be extended beyond three rounds. McIlroy also needs Uihlein to be halted elsewhere. Perhaps, quietly, he would not mind a less arduous scenario with Augusta looming.

“I didn’t really necessarily play badly,” McIlroy said. “He played pretty well. He was a few under through nine and he didn’t make a bogey all day. So it was hard to claw my way back.

“It was gusty out there; the conditions were a little tricky. I made a run at him at the end but it was a little too late.”

It was, therefore, a case of the highs of Bay Hill to the lows of Austin for McIlroy. Perhaps the exertions associated with Sunday’s stunning success had a strong impact. Uihlein, the world No 63, delivered three birdies when reaching the turn 4 up, an advantage that proved insurmountable to McIlroy.

The four-times major champion, however, battled back admirably. Having been five down after 13 holes, McIlroy won three in succession. A half in par at the penultimate hole proved sufficient for Uihlein to claim the point.

Ian Poulter emerged victorious by 3&2 from the all-English battle against Tommy Fleetwood. Poulter insisted he has “never been more motivated” as he seeks to earn a Masters berth.

“Winning match play is always really pleasing,” said Poulter, who excels in this format. “Tommy is a great player. I don’t think either of us really holed any putts. I probably played just a little better than he did and obviously got it done.

“The simplicity of match play is win your match. It sounds really easy and it’s not. So it’s about a level of focus and level of concentration this week. Be super aggressive, try not to hand too many holes away.

“It’s a tricky golf course. It’s easy to get out of position and it’s easy to hand holes to your guy with not really doing too much wrong. I’m happy with the win.”

Jason Day, a former winner in Austin, enjoyed a 4&2 triumph over James Hahn but Jordan Spieth was only partly content with a scrappy 2&1 victory over Charl Schwartzel.

“I think I shot 12 under when this tournament was at Harding Park and didn’t make it out of the group stage,” Spieth recalled. “I probably shot five under against Lee Westwood and lost. There’s probably numerous times that has happened.

“Today I was leading and over par for the day at one point. Sometimes that happens too. That’s why this tournament, to an extent you can say it has a bit of luck to it.

“But, at the same time, look at the recent winners. They are the guys playing the best going in and they were the best in the world at the time and they won. So you can look at it both ways.”

Alex Norén’s star continues to rise on this side of the Atlantic, the Swede securing a 4&2 success over Kevin Na. The Englishman Tyrrell Hatton saw off Alex Levy 3&2 while Justin Thomas defeated Luke List 2 up.