The golf marathon begins this week at Royal Troon. The British Open begins a grueling stretch of championship-caliber golf, including the PGA Championship in two weeks and the Olympics starting another two weeks after that. Add in the FedEx Cup playoff events and the Ryder Cup and that equates to two things: exhausted professionals and elated golf fans.

Here are five things to watch for in Scotland starting Thursday:

More brilliance from DJ

Dustin Johnson may have finally figured out his game. And if that’s the case, the rest of the golf world has been put on notice. After winning the U.S. Open last month, he came back two weeks later and won the WGC-Bridgestone Championship. He’s now ranked No. 2 in the world rankings, a career best. Watch out Mr. Spieth.

Laser focus for Spieth

Jordan Spieth demonstrated how focused he is by announcing earlier this week that he will not be playing in the Olympics next month in Brazil. Spieth joins Rory McIlroy, Jason Day and Johnson as players (they are the top four in the world rankings) who will be absent from the 60-player field. It’s a bad blow for the Games.

On Sergio watch

Sergio Garcia not yet won a major, but the 36-year-old Spaniard always seems to play well in the British Open. He has nine top-10 finishes in his last 14 Open starts. That includes a second-place finish in 2014 and a T-6 at St. Andrews last year. He won the Byron Nelson back in May and earned a T-5 at the U.S. Open. He’ll be on the leaderboard at some point this weekend.

USA! USA! USA!

Sideways rain and gale force winds, typical weather for a British Open, aren’t exactly what you’d call ideal conditions for many American golfers. But for whatever reason, the last six times the Open has been staged at Royal Troon, the course has produced an American champion. Arnold Palmer and Tom Watson are on that list, with the last being Todd Hamilton in 2004 when he beat Ernie Els in a playoff. Is the seventh time another American charm?

Royal challenge

For a British Open setting, nothing compares to the Old Course at St. Andrews. But Royal Troon is no slouch with its prevailing wind that shows its teeth on the back nine. The last two hours on Sunday can’t come soon enough. And considering a no-name like Hamilton can win this thing, the Claret Jug is truly up for grabs.

Marc Figueroa is a freelance writer who has been covering golf in San Diego for more than 20 years.