Rory McIlroy and Bryson DeChambeau at wrong end of Open leaderboard on day one

US Open rivals Rory McIlroy and Bryson DeChambeau found themselves together at the wrong end of the leaderboard on day one of the 152nd Open.

A month after McIlroy’s nightmare finish at Pinehurst helped DeChambeau claim a second US Open title, the pair were facing an uphill battle simply to make the cut in the year’s final major at Royal Troon .

McIlroy was level par after seven holes of his opening round before running up a double bogey on the signature par-three eighth, the Northern Irishman’s first attempt to escape a bunker on the Postage Stamp coming back to his feet.

After also dropping a shot on the 10th, McIlroy then carved his tee shot on the difficult 11th out of bounds towards the adjacent railway line, another double bogey dropping him to five over par.

DeChambeau has been in brilliant form in the majors this season, finishing sixth in the Masters and runner-up in the US PGA Championship before edging out McIlroy at Pinehurst thanks to a stunning par save from a bunker on the 72nd hole.

His record in the Open is not so impressive, however, with just one top 10 in six starts and the 30-year-old was competing at Royal Troon for the first time as he only turned professional three months before it last staged the Open in 2016.

DeChambeau acknowledged during practice that the back nine – which is usually played into the wind – “has some teeth” but with the wind switching directions, it was the front nine which caused him all sorts of problems.

After three-putting the first, a wayward drive on the third cost DeChambeau another shot and he also bogeyed the fourth before running up an adventurous seven on the par-five sixth.

Despite his strength, DeChambeau could only advance his second shot a few yards from heavy rough, then hit his next onto the adjacent 13th fairway, missed the green with his approach and took three more shots to get down.

Fellow American Justin Thomas had set the early clubhouse target on three under par thanks to birdies on the 17th and 18th, the two-time major winner having reached four under after 10 holes before a double bogey on the 12th.

Sweden’s Alex Noren , who only secured his place in the field via a tie for 10th in the Scottish Open on Sunday, was a shot off the pace alongside Ryder Cup team-mates Justin Rose and Nicolai Hojgaard.

Noren carded four birdies and two bogeys in his 69, with playing partner Calum Scott, a 20-year-old Scottish amateur, also safely in the clubhouse on level par.

Former champion Justin Leonard had got play under way at 6.35am, the 1997 winner at Troon returning a nine-over-par 80 that was two shots better than 2004 champion and playing partner Todd Hamilton.

“The opening tee shot was probably the best shot I hit all day,” Leonard admitted.