MEXICO CITY — Phil Mickelson knew this was coming, even when he had so little to show for it.

Mickelson had gone 101 tournaments around the world since he last won at Muirfield in the 2013 British Open, which moved him to No. 2 in the world and gave him the third leg of the career Grand Slam. In more than two decades on the PGA Tour, he had gone only two seasons without winning.

And then it was up to four straight years and counting.

There was more frustration than self-doubt. And with Mickelson, even at age 47, there was never a loss of confidence.

"I knew that wasn't going to be my last one, no," he said Sunday. "And this isn't either."

The most recent one came in the high altitude of the Mexico Championship, and it was another pulsating performance, as often is the case with Mickelson.

Five birdies in the opening 10 holes gave him the lead. Right when he was on the verge of taking control, he went for the green on the par-5 11th hole only for the shot to carom off a tree and into the bushes near the edge of Chapultepec Golf Club. Deep in the bushes, he blasted out and hit the crowd. He wound up making bogey. Then came another wild drive that bounced along the cart path, forcing him to scramble for par.

Three groups ahead of him, Justin Thomas delivered the shot of the tournament. Eleven shots behind going into the weekend and suddenly tied for the lead, Thomas holed out from 119 yards on the final hole for eagle to cap off a 62-64 weekend as he went for his second straight victory.

"I didn't know that he holed out," Mickelson said. "I just saw that he finished at 16 under when I was playing the 15th, and that meant that I needed to birdie two to get even with him."

And that's what he did. A perfect drive and a 6-iron for a two-putt birdie, and then a 20-foot birdie on the 16th.

Mickelson closed with a 66 and headed to a sudden-death playoff with Thomas, a duel between players separated by 23 years of age. Missing from the group was Tyrrell Hatton, who delivered his own charge with four straight 3s on his card, the last one an eagle to tie for the lead. But he missed the 18th green with a wedge, chipped strong and missed the par putt.

The sudden-death playoff ended quickly. Thomas went long with a gap wedge to the par-3 17th and chipped to 10 feet short of the hole. Mickelson hit the green, narrowly missed the birdie putt and walked off a winner — finally — when Thomas missed his putt.

The disappointment was tempered by the guy who beat him.

Mickelson took interest in Thomas before he even reached the PGA Tour. They played a practice round at the 2014 U.S. Open, and Mickelson said that day to the media, "You'll get to know Justin Thomas soon enough."

Thomas, the PGA Tour player of the year last season and already a two-time winner this season, moved to No. 2 in the world.

He is the type of player — along with Dustin Johnson, Jordan Spieth, Jon Rahm, Jason Day and Rory McIlroy — who represent a powerful young generation that Mickelson now has to beat if he wants to reach one of his goals.

Mickelson, who captured his third World Golf Championship, now has 43 victories on the PGA Tour. The first was in 1991 — before Thomas, Spieth and Rahm were even born — when he was an amateur. He has long said he wants to get to 50.

The more pertinent number might be 48. That's how old Mickelson will be in June. No one has won more than five times on the PGA Tour after turning 47.

"Oh, I will," Mickelson said about reaching 50 titles. "I'll get there."

That's not all he wants. One of his chief goals for the year was to be on his 12th consecutive Ryder Cup team for a chance to win in Europe, which he has never done. The victory should be enough to move him to No. 4 in the standings. Given his value in the team room, winning the Mexico Championship makes it hard to overlook Mickelson.

Left unsaid is the U.S. Open, the only major keeping him from the career Grand Slam. It returns this summer to Shinnecock Hills, where Mickelson was on the cusp of winning the last two times in 1995 and 2004.

For now, the focus is on the Masters and a chance to add a fourth green jacket.

"I needed to get a win before Augusta so I wasn't trying to win for the first time in four-and-a-half, five years at that event," he said.

He got his validation in Mexico City. It was meaningful because it was the first victory since he began working with Andrew Getson, and the first victory with his younger brother, Tim, as his caddie. And it was the next victory, no matter how long it took.

"I don't think this is the peak," he said. "I think I'm going to continue to get better."