American golfer Dustin Johnson celebrates his crucial chip-in eagle on the 16th hole at the Sheshan International Golf Club.

Story highlights

Dustin Johnson wins the WGC-HSBC Champions tournament by three strokes Sunday

American loses lead in first two holes of final round but plays last six in five under par

Defending champion Ian Poulter finishes second ahead of Graeme McDowell

McDowell closes gap on Race to Dubai standings leader Henrik Stenson

CNN  — 

Patience is finally paying off for Dustin Johnson. One of the most naturally gifted golfers in the world, he feels he is now closer to fulfilling his promise after clinching the “biggest win” of his career in circumstances that might previously have proved too testing.

The big-hitting 29-year-old claimed the $1.2 million first prize at the HSBC Champions in Shanghai on Sunday, winning his first World Golf Championships title by three shots after a sizzling finish.

Next, he hopes, is the holy grail of any player – a win at one of the four majors.

“This is the biggest win of my career and hopefully there are better things to come. A major is always the next step,” the American told reporters.

“Am I suited best for one or the other? I don’t think so. I think they all suit me very well. If I play like I did this week, I’m going to win one for sure.

Read: Johnson ‘mad’ after Shanghai lapses

“I grew up right down the street from Augusta (venue for April’s Masters), so that would be my favorite one. I just love playing that golf course.”

Johnson has already gone close twice, having led by three shots going into the final round of the 2010 U.S. Open before blowing up and then missing out on a playoff at the following year’s PGA Championship after getting a two-shot penalty at the last hole.

In China, where he was chased by defending champion Ian Poulter and Graeme McDowell – the man who overhauled him to win at Pebble Beach three years ago – he also had a three-shot lead.

But it was gone inside two holes as he three-putted his first and Poulter began with two birdies.

Read: Johnson surges five clear in Shanghai

However, Johnson is mentally stronger these days and he tussled for the lead with Poulter before chipping in for an eagle at 16 that put him two clear of the Englishman, and then picking up another shot at 17 before parring the final hole – which he had double-bogeyed on Saturday.

“It takes a while to learn,” Johnson said of his newfound maturity, having carded a second successive six-under-par 66 to clinch his second PGA Tour title this year and first of the new 2013-14 season.

“I wish I would have had some of that a few times a few years ago, but you learn from your mistakes and try to get better from them.

“I think I showed a lot of patience and a lot of discipline with clubs I picked and shot selection.”

Poulter, who also closed with 66 after a 63 on Saturday, moved up to fourth in the European Tour’s Race to Dubai standings – WGC events, like majors, count for points on both main circuits.

“I guess it was a good defense,” the 37-year-old said. “Obviously I’m a little disappointed not to put my hands back on the trophy, but 15 birdies and an eagle at the weekend is some pretty good golf.

Read: McIlroy claims early lead in China

“I’m in great form. I really am playing well. The work I’ve done leading up to this run of tournaments has really worked and I couldn’t be hitting it any better right now.”

McDowell was third, another shot back on 20-under 268, as he trimmed Henrik Stenson’s Race to Dubai lead ahead of next week’s third event in the final series in Turkey.

The Swede, who won the PGA Tour’s FedEx Cup in September, finished tied for 31st at Sheshan International after a closing 65.

McDowell paid tribute to Johnson, who is a key member of the U.S. Ryder Cup team.

“Dustin was in a different league off the tee and gave us a little bit of a sniff – and then promptly slammed the door,” the Northern Irishman said.

“He’s just a quality, talented, very athletic, classy player. Yeah, he makes mistakes. But when you’ve got a game as good as him, you can get away with a few mistakes. He’s got a great wedge game to go with an outrageously good driving game.”

Spain’s Sergio Garcia was fourth on 18 under after shooting the day’s equal-best round, a flawless nine-birdie 63.

U.S. Open champion Justin Rose was two shots back after a 68, just ahead of former world No. 1 Rory McIlroy and Canada’s Graham DeLaet (both 69).

Bubba Watson and Martin Kaymer were tied for eighth with Jamie Donaldson, just ahead of Ernie Els, Keegan Bradley and Boo Weekley in 11th equal.

American veteran Phil Mickelson was 14th after the British Open titleholder carded 65.