Rory McIlroy believes he has to make a strong start at the US Open if he is to mount a serious challenge for the top prize at Pebble Beach.

The Northern Irishman has four major titles to his name so far and in each of those successes he has either been in the lead or a shot off the pace after the first round.

“If you look at the history of major championships, that first round is so important,” said McIlroy, as reported by the Evening Standard.

“The majors I’ve won, I’ve started every one really well.” McIlroy hit a first-round 73 at the Masters and a 72 at the PGA Championship this year, which meant he has had to play catch-up in both majors so far.

At the Masters he came in a tie for 21st, but at the PGA Championship at Bethpage he managed to fight his way up the leaderboard and finish in a tie for eighth.

McIlroy is convinced he can challenge for a second US Open crown, having won the tournament eight years ago, and is well aware how he starts at Pebble Beach will be key.

“My first rounds at Augusta and Bethpage put me behind the eight ball,” he added.

“It’s hard to catch-up, especially with major championships being played on the toughest courses.”

McIlroy is 9.50 to win the US Open, defending champion Brooks Kopeka is 10.00 and 2019 Masters winner Tiger Woods is 12.00.