Brooks Koepka made an ominous start to his bid for an historic third straight victory in the US PGA Championship as Tiger Woods kept himself firmly in the hunt on a top-class leaderboard in San Francisco.

Koepka carded an opening four-under-par 66 at Harding Park to lie a shot off the early clubhouse lead held by former world number one Jason Day, the Australian carding five birdies in a flawless 65.

Former Ryder Cup team-mates Justin Rose and Martin Kaymer were alongside Koepka on four under, with Open champion Shane Lowry two strokes further back following a 68 matched by Woods.

Starting on the back nine, Koepka failed to take advantage of the par-five 10th and dropped a shot on the next, but then birdied the 13th, 14th, 16th and 18th thanks to some superb approach play.

A bogey on the first slowed Koepka’s momentum, although he did well to limit the damage to a single shot after only moving his second shot 40 yards from the rough and then finding a bunker with his third.

Koepka, who had managed just one top-10 finish in nine starts either side of the Covid-19 shutdown before last week’s tie for second in Memphis, bounced back with birdies on the second and fourth and declared himself satisfied with his opening effort.

“I feel good. I feel confident. I’m excited for the next three days,” Koepka said. “I think I can definitely play a lot better, and just need to tidy a few things up, and we’ll be there come Sunday on the back nine.”

Koepka’s first attempt to win the same major three years in a row came up just short in last year’s US Open and he added: “I think that drove me nuts a little bit. I played good golf, but I just got beat by Gary (Woodland).

“To do it here would be special. I think there’s, what, six guys that have ever won three in a row. Yeah, not a bad list to be on.

“The whole goal every time we tee it up in a major is to win them. The whole year is spent prepping for these four.”

Woods was two under par after four holes, fell back to level par and then fired three birdies in four holes before making a bogey on his penultimate hole at a venue where he won a WGC event in 2005 and compiled a 5-0 record in the 2009 Presidents Cup.

The 15-time major winner, who is using a slightly longer putter this week to ease the strain on his troublesome back, said: “It’s difficult for me to bend
over at times, and so practising putting, I don’t spend the hours I used to.

“It wasn’t unusual for me to spend four, five, six hours putting per day. I certainly can’t log that with my back being fused. Most of the guys on the Champions Tour have gone to longer putters as they have gotten older, because it’s easier to bend over, or not bend over.”

Playing alongside Woods, Rory McIlroy and world number one Justin Thomas shot 70 and 71 respectively, McIlroy battling back from a hat-trick of bogeys on his front nine with three birdies in four holes around the turn.

“It was there for the taking today,” McIlroy said. “I feel like I definitely could have been a few shots lower, but I sort of grinded it out and, with how I hit it on the back nine, even par actually wasn’t too bad.

“Need to hit a few more fairways tomorrow to try to attack some pins and get
it closer, and not leave myself four and five-footers for par all day.”

Kaymer has not won since the second of his two major victories in the 2014 US Open and revealed he watched a replay of the back nine of the final round on YouTube on Wednesday evening.

“Definitely that video helped me to believe that my putting was good enough; that my ball-striking was good enough, even though it’s a few years back, but it’s always nice to remember those moments and feel the same that you felt that day,” said Kaymer, who won the 2010 US PGA at Whistling Straits.

“I know you shouldn’t live in the past, but if the past can help you in the present moment, I’ll take it.”