The pursuit of major glory at the U.S. Open got underway after a fog-enforced delay on Thursday, with favourite Jon Rahm among a host of contenders primed for action at Torrey Pines.

As two groups went out after the fog had cleared at around 08:15 local time at the first and 10th holes, around an half and half later than planned, the big names were waiting in the wings, with Rahm hotly tipped for success.

Rahm, who suffered a coronavirus-enforced withdrawal when he led after three rounds at the Memorial Tournament this month, is scheduled to head out at 15:36.

The Spaniard has never won a major and has a best finish at the U.S. Open of third in 2019.

Reigning champion Bryson DeChambeau will begin his title defence at 15:14 in a group with Masters holder Hideki Matsuyama and Tyler Strafaci.

DeChambeau's rival Brooks Koepka, who won back-to-back U.S. Opens in 2017 and 2018, can attempt to apply some pressure when he goes out at 09:29 with Justin Thomas and last year's US PGA Championship winner Collin Morikawa.

The man who took that honour from Morikawa, Phil Mickelson, can complete the Grand Slam this week, and Lefty will tee off his bid to join that elite club at 09:51. He has been runner-up six times in this event.

Rory McIlroy, a winner in 2011, will seek to add a fifth major when he gets his tournament up and running at 15:36 alongside 2013 champion Justin Rose and world number one Dustin Johnson.