Top-ranked Scottie Scheffler launches his bid for back-to-back major titles as the US Open gets underway on Friday (Manila time).

The world’s top golfers face an ultimate challenge at Oakmont, where dense rough, sloped fast greens and tricky bunkers have Scheffler among many calling it the hardest course they might ever play.

“This is probably the toughest golf course in the world right now,” defending US Open champion Bryson DeChambeau said.

Scheffler noted the tall rough, saying, “What’s so special about this place is pretty much every time you’re off the fairway it’s going to be very difficult for you to get the ball to the green.”

Scheffler, whose nine wins last year included Paris Olympic gold, has won three of his past four starts and his matchup against iconic Oakmont is golf’s version of a heavyweight showdown.

It begins at 1:25 p.m. (1725 GMT) when he starts off the first tee alongside fourth-ranked American compatriot Collin Morikawa and Norway’s Viktor Hovland.

After capturing last month’s PGA Championship for his third major crown, Scheffler is trying to become the first man to win consecutive majors since Jordan Spieth in 2015 by taking his first US Open title.

Scheffler is a heavy oddsmakers’ favorite but tries to ignore such things, especially after bettors forced him to dump his Venmo account.

“I was either getting paid by people or people requesting me a bunch of money when I didn’t win. It wasn’t a good feeling,” Scheffler said.

Second-ranked Rory McIlroy, who won the Masters in April to complete a career Grand Slam, and DeChambeau, who won last month at LIV Golf Korea, will be among the first to test Oakmont after Indianapolis dentist and former Oakmont caddie Matt Vogt hits the opening shot off the first tee at 6:45 a.m.

Five-time major winner McIlroy, who says he has seen progress after driver struggles in the past month, begins off the 10th tee at 7:40 a.m. with playing partners Justin Rose of England and Shane Lowry of Ireland.

Northern Ireland’s McIlroy could become only the seventh player to win the Masters and US Open in the same year, joining Tiger Woods, Jack Nicklaus, Spieth, Arnold Palmer, Craig Wood and Ben Hogan.

DeChambeau, seeking his third US Open victory in six years, goes off the first 10 at 7:29 a.m. alongside fourth-ranked US countryman Xander Schauffele, the reigning British Open champion, and Spain’s Jose Luis Ballester, the reigning US Amateur champion.

Phil Mickelson, who turns 55 Monday, can complete a career Grand Slam with a victory. He starts at 8:02 a.m. off the 10th tee, two groups behind McIlroy.