Two-time winner Brooks Koepka shone as defending champion Bryson DeChambeau faltered in a US Open first round that was left uncompleted because of fog.

A 90-minute delay to the start of play at Torrey Pines meant 36 players did not finish because of fading light.

Koepka finished two behind clubhouse leader Russell Henley on two under while DeChambeau ended two over.

Rory McIlroy rushed to finish, jogging up the last before rolling in a birdie, to card a one-under 70 in California.

World number three Jon Rahm also completed his round just before darkness descended, parring the ninth to sign for a 69 and sit alongside Masters champion Hideki Matsuyama and Americans Xander Schauffele and Hayden Buckley.

America's Henley was joined on four under by Louis Oosthuizen but the South African must complete his opening round on Friday because the hooter sounded to signal the end of play while he was playing his 17th hole.

England's Matt Fitzpatrick, Tyrrell Hatton and Richard Bland all finished their rounds on one under, while Lee Westwood and Scotland's Robert MacIntyre are one back after carding 71s.

Phil Mickelson, 51, is chasing a career Grand Slam but his slow start saw him finish on four over.

The San Diego native became the oldest major winner when he won his second US PGA Championship in May and is once again seeking to add the US Open title to his collection, having finished as runner-up six times.

Italian Francesco Molinari and Spain's Rafa Cabrera Bello lead European hopes on three under par.

As the skies cleared the conditions were favourable for early starters, but those who began later had stronger winds to contend with and 36 players will have to complete their first round before starting their second on Friday.

Play is scheduled to resume at 06:50 local time (14:50 BST), although more morning fog is forecast on the Pacific coast.
Koepka starts strongly as DeChambeau struggles

DeChambeau brushed off an ongoing social media feud with Koepka as "banter" earlier in the week. but the world number five looked distracted in his opening round.

The spat seemed to reach its zenith recently when Koepka posted a social media video offering free beer to fans who were ejected from an event for heckling DeChambeau.

The defending champion's tactic of overpowering a typically tricky US Open course worked when he won at Winged Foot last September and he had promised to "bomb and gouge" his way round Torrey Pines but things did not go to plan this time.

The 27-year-old seemed to lose his composure as the round went on and unravelled on the par-five 13th. His second shot ended up in a divot and his third in a bunker.

That led to one of DeChambeau's six bogeys as he struggled with his short game, before a birdie on the 18th kept him in touch with three rounds still to play.

Koepka, who is chasing a third title in five years after wining in 2017 and 2018, looked in control early on and, after starting his round on the 10th hole, the 31-year-old took the solo lead with his fourth birdie of the day on the second - his 11th hole.

But the two-time PGA Championship winner came undone with bogeys on the third and seventh, before finishing off with two pars to card a 69.

Mickelson started more sluggishly and frequently missed the fairway, bogeying three of his first six holes, and a birdie on his eighth hole did little to fix the damage with two more bogeys before he was home.

American Henley's day substantially improved after his opening bogey, with back-to-back birdies on the seventh and eighth. A bogey on the 12th was the only blight on a back nine in which he claimed three more birdies.

Oosthuizen was the best of the late starters, holing three birdies in a row from the seventh. The 38-year-old former Open champion chose to stop when the hooter sounded, rather than rush a birdie putt on his 17th hole.

McIlroy among Europeans who made their mark

In a tournament historically dominated by Americans, several Europeans made promising starts.

Northern Ireland's McIlroy stated his intention to "freewheel" to make up for the slow starts that have hindered his major performances since he won his fourth and last big title in 2014.

All went to plan initially as he birdied the first and did the same on the seventh with a crowd-pleasing chip-in, but two bogeys on the back nine pushed the 2011 champion down the leaderboard before his late birdie finish.

England's Bland had won his first European Tour title at the 478th attempt in May to qualify for this week and the 48-year-old kept up his form with an impressive showing.

He was one shot off the lead after three birdies in his opening 12 holes, before bogeys on the 13th and 14th meant he slipped to one under.

Compatriot Marcus Armitage had also claimed an emotional first European Tour win earlier in June and the 33-year-old finished round one of his US Open debut on level par after a birdie and bogey on each half of the course.

Earlier in the day Francesco Molinari - the 2018 Open champion - made a late charge with birdies on the 16th and 18th, while brother Edoardo made it round in a one-under-par 70.

The round was made more special by the fact the brothers had this week been reunited for the first time in 18 months, having been separated because of travel restrictions caused by the coronavirus pandemic.

"We text and we talk pretty often," Francesco said. "But obviously it's not the same, especially after such a long time. It's definitely the first time that we've been apart for so long, so nice to see him."

Spaniard Cabrera Bello's round sprung to life with an eagle on his ninth hole and he carded a 68.

Tommy Fleetwood enjoyed three birdies on the front nine, but blundered after the turn and a double bogey on his 14th hole contributed to a one-over-par 72.

Ireland's Shane Lowry went one better with a triple bogey on the fourth hole but the 2019 Open winner fought back to finish alongside Fleetwood.

Justin Rose, the 2013 champion, struggled to a 78 but he did enable his group, which included McIlroy and world number one Dustin Johnson, to finish off by running to the 18th tee and hitting his drive before play was suspended.

His tee shot almost hit Sergio Garcia up ahead in the fairway but because the group had started before the hooter sounded, they were allowed to complete the hole, Johnson recording a par to finish level for the round.