The most fickle tournament in golf was no match for the so-called modern version of the Big Three.

Jordan Spieth, Jason Day and Rory McIlroy all reached the round of 16 in the Dell Match Play, which on paper would not seem like that great of a feat. But consider that it hasn't happened in 10 years, when the top three players in the world ranking were Tiger Woods, Vijay Singh and Retief Goosen.

Three days of round-robin play ended at Austin Country Club with a few peculiar outcomes.

Nine players who went 2-1 were out of the tournament, including Phil Mickelson.

Two players who only won one match were still playing, including PGA Tour rookie Patton Kizzire, who is becoming the most intriguing character going into the knockout stage. Kizzire wasn't even sure he was in the 64-man field at the deadline for qualifying. He has birdied the 18th hole all three days to earn two unlikely halves and one big victory. And he's still holding out hope of advancing far enough to get into the Masters.

But that's the danger of this event. No match is easy. There are no favorites. And there's no point looking ahead beyond the next match.

Go back to 2006 when the top three reached the quarterfinals. Woods and Singh were beaten the next morning, and Goosen lost the next afternoon.

"It only gets harder from here," said Patrick Reed, one of the survivors. "The guys who make it to the weekend are the guys playing the best right now."

THE BIG THREE: Spieth, Day and McIlroy took different routes to the round of 16.

Spieth has never trailed in any of this matches, and he has been 3 up by the sixth hole in all of them. Friday against Justin Thomas was no different as Spieth was 4 under through five holes and Thomas never got any closer. Day had it even easier. He played six holes when Paul Casey withdrew with a stomach illness, meaning Day went 3-0 in his group and got extra time to rest his sore back.

McIlroy had the toughest day. He never led until the 15th hole against Kevin Na, gave it back on the next hole, and they had to go to overtime because both finished group play at 2-0-1. McIlroy won with a 6-foot par on the second extra hole when Na hit his drive into a hazard.

McIlroy now has played Na twice in Match Play. They have gone 38 holes. McIlroy is 2-0.

THE BIG PERFORMANCE: Reed and Zach Johnson might be playing as good as anyone going into the weekend.

Reed joined Spieth as the only players who have never trailed, and he drilled Mickelson in a winner-take-group match on Friday. Reed won the first two holes with pars, two more with birdies and then made an eagle on No. 6. He holed out for eagle on No. 10 to go 7 up.

Mickelson's only birdie to win a hole was on No. 13. By then, the match was dormie.

Johnson, meanwhile, has been so dominant that he hasn't had a match go beyond the 15th hole. He ended his third match early enough against Shane Lowry that he decided to play the last three holes to make sure he remembered what they were. Johnson had not played them since Tuesday.

He faces Zach Johnson, while Reed gets Dustin Johnson.

THE PLAYOFFS: Extra holes were inevitable in a format that had no tie-breakers, but Friday was peculiar on a couple of fronts.

McIlroy and Na were in a winner-take-all match, so when it ended, they headed to the first tee for a playoff. That was simple.

In other groups, Dustin Johnson beat Jimmy Walker, and then had to play one hole with Kiradech Aphibarnrat, who had beaten Robert Streb. Johnson won with a birdie. Byeong-Hun An lost the 18th hole to Rickie Fowler and got into a playoff with Scott Piercy, who won the 18th hole against Jason Dufner. An beat Piercy. Go figure.

The strangest was Branden Grace and Chris Kirk, who each won their matches handily. They had to wait nearly three hours for their playoff, and it was over quickly when Grace went from a fairway bunker over the green and had to scramble for bogey.

THE LINEUP: Spieth vs. Louis Oosthuizen, Day vs. Brandt Snedeker, McIlroy vs. Zach Johnson, Bill Haas vs. Kirk, Matt Kuchar vs. Brooks Koepka, An vs. Rafa Cabrera-Bello, Kizzire vs. Ryan Moore, Dustin Johnson vs. Patrick Reed.

The winners advance to the quarterfinals Saturday afternoon.