Justin Rose was a 17-year-old amateur with no expectations when he somehow found a way to compete on the final day in the British Open.

He was 32 when he finally won his first major championship, outlasting Phil Mickelson two years ago in the U.S. Open at Merion outside of Philadelphia.

Now he's the No. 5 player in the world and a contender almost every time he tees it up. That includes a final group pairing with Jordan Spieth in the Masters that didn't get him a green jacket but left him brimming with confidence coming into this Open at Chambers Bay.

"I feel like I've kicked on from winning my first major, sometimes it's difficult to live up to that," Rose said Wednesday. "I've won tournaments; I've done all the right things. Again, Augusta was another sign this year. I came up against a great Jordan Spieth performance, but again it was a sign that my game was capable of winning these big championships."

Rose has already pocketed one win this year, taking the Zurich Classic in New Orleans. He almost won again in his last outing, losing in a playoff at the Memorial to David Lingmerth.

He feels like he's come into his own as a player who should be in the mix anytime he tees it up in a major championship.

"I'm 34. Let's say the next six to 10 years are going to be more of my prime," Rose said. "I think from 30 to 40 I always felt was going to be the time where I was going to have to step up and win a major, to get that done relatively early in that time frame has been great. Let's call it six years, that's 20 plus, 24 majors that are going to come around. I feel like if I just keep doing what I'm doing that's going to throw up quite a few opportunities."

It's been a long climb for the Englishman, whose game sagged badly when he turned pro the year after he finished fourth as a teenager at Royal Birkdale. At one point he missed 21 straight cuts on the European Tour as he searched for answers.

But the father of two, who now lives in the Bahamas, retooled his swing and broke through with four wins internationally in 2002 before joining the PGA Tour. Now he's a major champion whose biggest worry is managing his time with his family while at the same time keeping his game in fine tune.

"It all happens at once," Rose said. "You're in the prime of your golfing career, and you're also in a sense in the prime of your life with young kids. Everyone tells you when you have kids how quick it goes and you blink and they're teenagers. You're trying to absorb as much as you can at home and make the most of your career. So it's definitely a fine line to balance. But it's very rewarding when you get the balance."

Rose drew a pairing in the first two rounds with Spieth and Jason Day, two players he's very familiar with. He has played with Spieth in three tournaments this year, including the final rounds at the Masters.

"It's a great pairing," Rose said. "I enjoy playing with Jordan. I think in some ways I've got to learn his game pretty well. It's going to be a fun three ball to be a part of."

Even more fun for Rose would be to be in the mix on Sunday, much like he was at Merion when he posted a score that none of the players behind him could beat.

Chambers Bay is an entirely different course than Merion, but Rose sees similarities. Par is usually a good number at the Open, and the rewards usually come with patience.

"I think the mentality is going to be the same in terms of having to grind out pars, having to be patient, having to handle the adversity that's going to happen out there in 72 holes of golf," he said. "As long as I play well that should manifest itself in a pretty good chance to win. Then it's all about coming down the stretch on Sunday."