Australia's resurgent two-time Match Play champion beat Frenchman Victor Perez 2&1 at Austin Country Club to go top of Group 9 with a 2-0 win-loss record.

After charging home with six consecutive birdies to crush Canadian Adam Svensson 4&2 in his opening match, Day conceded he needed some luck to see off Perez on Thursday.

"Today was a little bit scrappy but coming off yesterday's round I felt pretty good about my game," he said.

"I was with my coach last week and I'm just trying a few different things with my swing and it's a good test to see how well it copes under pressure. It feels like you're playing Sunday pretty much every round here.

"So I'm very happy."

Day can secure a place in the last 16 with a win or a tie in his final group match on Friday against Morikawa, who stole a crucial half point in a squared encounter with Svensson.

Chasing a Masters invite, Lucas Herbert is undefeated so far this week in Austin. PHOTO: Ben Jared/PGA TOUR via Getty Images.

The resurgent Day is bracing for a torrid contest to stay alive at the cut-throat Masters lead-up event.

"You know that he's going to be around all day," Day said of Morikawa.

"If he has a good day with the putter, that's going to be difficult.

"But I just need to focus on myself. It's not going to be perfect every single day but I'm excited for the challenge."

Countryman Lucas Herbert (2-0) is in control of Group 14 after taking down Tyrrell Hatton (0-2) 2&1.

Needing to make the quarter-finals to earn a Masters invitation, the 56th-ranked Herbert only needs to square his final group match against Ben Griffin (1-1) to advance to the knockout rounds.

"Today was a little bit scrappy but coming off yesterday's round I felt pretty good about my game ... It feels like you're playing Sunday pretty much every round here." - Jason Day.

Australia's other three players in the field face must-win matches to have a chance of progressing to the last 16.

Adam Scott finished 1-down against American Sam Burns to lose control of his destiny in Group 13.

Scott (1-1) needs to beat Adam Hadwin (0-2) next and hope Burns (2-0) loses to Seamus Power (1-1) to force his way into a sudden-death play-off to make the knockout stages.

Scott could have been in a much better position had he not driven into the hazard on the last hole to gift Burns the match.

But having trailed seven times during the day, and only hitting the lead for the first time on the 18th in his opening win over Power, the 2013 Masters champion eventually paid the price for living dangerously.

Min Woo Lee (1-1) succumbed 2&1 to reigning U.S. Open champion Matt Fitzpatrick (1-1) and needs to beat red-hot JJ Spaun (2-0) on Friday to have a chance to advance out of Group 11.

A tie will be enough for Spaun to progress after the American powered to a 5&4 victory over countryman Sahith Theegala (0-2).

And Cam Davis (1-1) remains a chance of escaping Group 6 after downing Tom Hoge 3&1.

But he will need to topple Aaron Wise (1-1) on Friday and hope Xander Schauffele (2-0) loses to Hoge to force a play-off with sixth-seeded Schauffele.

Davis must make the semi-finals to improve his ranking sufficiently to secure an invitation to Augusta National for the year's first major starting on April 6.

Rory McIlroy remained undefeated after accounting for Denny McCarthy 2-up, while Jon Rahm got his first win following a 4&3 defeat of Keith Mitchell.