Rory McIlroy opened with a birdie and followed with 13 straight pars. That's not a card that usually advances in the Match Play Championship, and yet the world's No. 1 player wound up winning in 14 holes.

Masters champion Jordan Spieth made seven birdies and had to go 16 holes.

And then there was Lee Westwood, who had five bogeys and a double bogey and won his match. That wouldn't have worked against Matt Kuchar, who had four birdies and only bogey. Then again, that didn't work for Kuchar. Just his luck that he ran into Ben Martin, who took the lead with a hole-in-one with a hybrid from 235 yards on the 17th hole.

A new golf course and a new format didn't change one aspect at the Match Play Championship. It was wild as ever on Wednesday.

The emotions weren't much different, either.

"Match play, you just need to beat the person that's in front of you, and I did that today," McIlroy said after his 5-and-4 win over Jason Dufner.

"Nobody wants to lose," Kuchar said. "I can assure you of that."

The difference this year at the TPC Harding Park is that no one has really lost — at least not yet.

The one-and-done format of the last 16 years, which made this World Golf Championship equal parts exciting and maddening, has switched over to round robin. There are 16 groups of four players, and the player with the best record after Friday advances to the round of 16. The other 48 players go home.

"Maybe I'd rather go home," Justin Rose said after losing, 3 and 2, to Marc Leishman. "I don't feel very hopeful right now. But I have a shot, so I guess that's a good thing."

Spieth, still equipped with that sporty short game, was conceded the last of his seven birdies from 3 feet on the 16th in his victory over Mikko Ilonen. The only misstep he had all day was the early move to take off his hat and shake hands. Ilonen needed to hole a bunker shot to have any chance to extending the match. When it came up 5 feet short, Spieth took his hat and went over to shake hands, and then he quickly put it back on when Ilonen didn't look his way.

That was only because Ilonen didn't realize Spieth was in tight. Once he saw his ball, the hats came back off.

"I played solid," Spieth said. "I'd take that the rest of the week."

As usual, plenty of big names lost early.

Defending champion Jason Day struggled off the tee and lost to Charley Hoffman. Henrik Stenson and Jimmy Walker lost in extra holes. Instead of going home, they have some hope.

"Obviously, I need to go out there and win the next two," Day said. "And whatever happens, happens. If I sneak through, I sneak through. If not, then it's my own fault for losing. It's a different format, and I'm looking forward to seeing how it goes the next couple of days."

In other matches:

— Hunter Mahan, one of five past champions in the field, had the shortest day in his 7-and-6 win over Stephen Gallacher of Scotland.

— Adam Scott had a birdie on the first hole and not another one the rest of the way. Francesco Molinari, who got into the field when Tim Clark chose not to play because of injury, beat Scott on the 14th hole.

— Only four of 19 holes were halved between Walker and Woodland. Walker sent it to extra holes with a birdie on the 18th, only for Woodland to win with a birdie on the next hole, the par-5 first.

— Kevin Na was 2 up with two holes to play when Joost Luiten birdied the 17th and 18th, and then the Dutchman won with a par on the first extra hole.

— Paul Casey won the longest match of the day, beating Chris Kirk in 22 holes. Casey made a 25-foot birdie putt on the 19th hole (the par-5 first), and Kirk halved the hole with a 10-foot birdie.

Even though the mass departure isn't until Friday, the second day of matches was shaping up to be significant. Eight of the matches are between winners, with perhaps the most compelling: Rickie Fowler against Shane Lowry, and Dustin Johnson against Charl Schwartzel.

Spieth played as though nothing had changed from a year ago. He told caddie Michael Greller not to check the painted dots on the greens that would indicate the pin positions for the Thursday rounds.

"I wanted us to look at it like it was win or go home," Spieth said. "I think I did see him checking on a couple of them. But I wanted that to be our mindset. There's going to be a lot of 2-1 scenarios in each group, so it's best not to worry about anything else."