Jimmy Walker never had more fun in such miserable weather.

The temperature was just above freezing, and it felt worse in a light rain. It was the kind of day to stay indoors, except that he was with his father and a longtime business supporter. And they were playing Augusta National.

"I think that's the only place on the planet you will go out and play when it's 38 and drizzling," he said. "What a great experience — my dad, staying in the cabins, played the Par 3 course. We did it all. It was ridiculous."

Thanks to a steady hand Sunday in a tense duel at the Frys.com Open, Walker gets to go back in even better circumstances.

Walker finally took the lead with a 6-foot birdie putt on the par-5 15th hole at CordeValle and closed with three pars for a 5-under 66 to win for the first time in his 188th start on the PGA Tour, and earn his first trip to the Masters.

Not that he needed a reminder, but tournament officials stuffed a yellow "Masters 2014" flag into the silver trophy.

"It's cool," Walker said. "To be able to go back and play in the tournament, it's another dream come true. It's going to be amazing."

Sunday proved to be little more than a learning experience for Brooks Koepka, the 23-year-old from Florida who helped make it easier on Walker over the final two holes. Koepka had control of the tournament all weekend, even building a four-shot lead with 11 holes to play, when he missed a 3-foot par putt on the ninth hole that changed the dynamics of the final round and eventually led to his demise.

Koepka missed a 6-foot par putt on the 11th hole to lose the outright lead. He made a few short putts to settle his nerves — 3 feet for birdie on the 12th, 6 feet for par on the 14th to stay tied — but the crucial moment came on a 6-foot birdie at the 15th that again missed to the left.

Trailing for the first time, Koepka pulled his tee shot on the 16th and had to scramble for bogey, and then hit 3-wood on the 297-yard 17th hole into the water, making another bogey and ending his hopes.

Koepka tried not to let the back nine ruin what has been — and still is — an amazing season.

He had no status on any tour, and then won three times on the Challenge Tour to earn a European Tour card. He showed so much promise that the Frys.com Open offered him an exemption without him asking, and he played between stops on Scotland and Shanghai.

He was close to earning a PGA Tour card. Koepka wound up tied for third, which gets him into Las Vegas next week before heading back to Shanghai and the BMW Masters.

"I can't get too down on this week," Koepka said. "I know I'll be criticized. But this year has been amazing. This week I played well. It happens to the best of them."

Vijay Singh closed with a 68 and wound up with the 27th runner-up finish of his Hall of Fame career, and his best result since he sued the PGA Tour in May over its procedure in investigating Singh's admission that he used deer antler spray.

Koepka tied for third with Kevin Na (64), Puerto Rico winner Scott Brown (64) and Hideki Matsuyama, the 21-year-old Japanese star who has joined the PGA Tour. Matsuyama, who played in the Presidents Cup last week, birdied his last three holes for a 66.

Billy Hurley III closed with a 68 and NCAA champion Max Homa from Cal birdied two of the last three holes to tie for ninth. That gets them in Las Vegas.

Along with the Masters, Walker also gets to go to Maui in January for the Tournament of Champions, another place he has never been, and he is assured a spot in the PGA Championship for only the fourth time in his career.

"I felt like I was good enough to be in them, play in them," Walker said. "There's always this big pressure to get into Augusta, and I would press here, press there. You want to be playing in the big stuff. That's what I'm aspiring to do — play against the world's best."

The Masters flag in the trophy was a subtle reminder of the new season.

The Frys.com Open previously was part of the Fall Series, a chance for most players to chase their PGA Tour cards after the FedEx Cup was over. The winner wasn't given a spot in the Masters. Now, it's the first official event of the tour's new 2013-14 season, treated with equal weight as the Phoenix Open and Pebble Beach, the Honda Classic and Houston Open.

Walker also cracked the top 50 in the world ranking for the first time in his career.

"Highest I've ever been ranked," Walker said. "I feel like I've got a nice trend curve going, and I just want to keep going up."