By Tony Jimenez

TROON, Scotland (Reuters) - The last six British Opens held at Royal Troon have been won by Americans and Dustin Johnson, the hottest player in golf, looks like he has all the credentials to send the U.S. into seventh heaven this week.

Not only did the big-hitting 32-year-old follow up his victory at last month's U.S. Open by capturing the prestigious WGC-Bridgestone Invitational title in Ohio, he also has a good record to boast about in the world's oldest major.

Johnson has finished in the top 14 in four of his seven trips to the British Open and came within a whisker of landing the coveted Claret Jug in 2011 when he wound up in a tie for second place behind Northern Ireland's Darren Clarke.

"He has a lot of spotlight on him this week because he has won the last two events he's played and they've been pretty big events," world number one Jason Day told reporters on the windswept Ayrshire coastline.

"He's typically played pretty well in the Open championship so he's obviously going to be a very tough guy to beat."

Johnson's surge to second in the world rankings has come as a surprise to some. His namesake Zach Johnson, however, believes it was always destined to happen.

"He's a supreme athlete and it just so happens that his sport for all of us, unfortunately, is golf," said British Open title holder Zach. "Not many guys can do what he does."

Day's form has also been pretty spectacular, having triumphed seven times in the past 12 months to rise to the summit of the rankings.

The Australian suffered a near-miss last year when he ended up in a share of fourth place at St Andrews.

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Winning a first British Open is clearly number one on Day's list of immediate priorities but hanging on to top spot in the rankings comes a close second.

"I think the stress of being number one in the world is a motivating factor for me just because I don't want to lose it," he said.

"It's really important for me to make sure I stick to my processes and do all the hard work I can to try to stay there for as long as I can."

Jordan Spieth won the U.S. Masters and U.S. Open in 2015 and is almost certain to figure prominently on the Troon leaderboard.

The 22-year-old American, however, has been the subject of intense scrutiny this week following his decision on Monday to opt out of next month's Rio Olympics due to health concerns.

With the benefit of hindsight, Spieth clearly would have made his announcement before Monday's Games deadline.

"I wish I could have made it as early as possible, not only for myself but also for Olympic golf, USA Golf," said the world number three.

"I certainly was not trying to wait until the last minute. I just couldn't make a decision and ... I was very indecisive with it."

The other member of the so-called 'Big Four' of world golf, Northern Ireland's Rory McIlroy, is pleased to be back at his home Open after being sidelined last year because of an injury he sustained while playing a friendly game of soccer.

"I guess it's the start of a new chapter for me in the Open championship," said the 2014 winner.

"It was very disappointing to miss last year but I'm determined not to miss any more for the foreseeable future and it's great to be back and have another chance to win another Claret Jug," added world number four McIlroy.

The year's third major begins on Thursday.

(Editing by Ken Ferris)