Li, who is trying to become the first player from China to win a men’s major championship, fired a bogey-free 65 to take a two-shot lead in the first major championship of the pandemic-interrupted season.
Li is at eight-under 132 heading into the weekend making him the first player from China to lead in a major.
Koepka kept his pursuit of a three-peat on track by shooting a hard-fought 68 to join five others in tie for second at six-under at TPC Harding Park in San Francisco.
First round co-leader Jason Day, England’s Tommy Fleetwood, Daniel Berger, England’s Justin Rose, and France’s Mike Lorenzo-Vera are all at six-under 134, two shots back of Li.
Brendon Todd, Paul Casey and Cameron Champ are another shot back at five under.
Li, who turned 25 on Monday, is hoping his solid play this week in San Francisco will revive the form that catapulted him to the upper echelons of golf with a third-place finish at the 2017 British Open.
He drained five birdies, including four on the front nine, making him the first player from China to hold a lead in a major championship. He has just one bogey through 36 holes.
“The last couple of days I’ve been pretty much all hitting in the right spot,” said Li. “Even if I miss the green, I still got a chance for an up-and-down.”
The weekend is going to be epic. https://t.co/IODGfHmoh9
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Li would also be just the second Asian player to win a major, joining South Korea’s Yang Yong-eun, who won the 2009 PGA Championship.
In 2012, Feng Shanshan made history by becoming the first player from China to win a major when she captured the women’s PGA Championship.
Asked what it is going to take for him to become the first Chinese male to do it, Li said he needs to drive the ball straight.
“Well, I still got two rounds left. A long way to go. I just want to play my best. If it happens, it happens,” said Li, who has two wins on the European Tour.
“I think the key on this course, you just need to hit as many fairways as you can, and especially putting and short game is quite important.”
Li got off to a hot start by making birdie on his first two holes, including a long 22-foot putt on the par-four number two.
On the first hole, Li blasted a 90-yard approach shot out of the rough to just three feet and then tapped in for a birdie.
He also had back-to-back birdies at the turn making putts of 12 feet on No. 9 and three feet on No. 10 for his only birdie on a par-five.
The conditions were challenging at times on Friday morning as the sun finally came out after several days of marine fog, but the winds also starting whipping around the course.
A MAJOR STAT–> 18 of Brooks Koepka’s last 22 major championship rounds have been in the 60s! https://t.co/f9EWdqKnva
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Koepka closed out his round with a birdie on No. 18 that was set up by a magical bunker shot.
“Incredible. That ball was a foot above my feet,” he said.
Koepka is bidding to become the first player to win the same major three consecutive times since Peter Thomson won The Open Championship from 1954-56.
“I like my position. I am excited for the weekend,” Koepka said.
Koepka had to seek treatment from the trainer on the 12th hole because of a sore hip but said it is not a big deal. “It is fine. It was just tight,” he said.
France’s Lorenzo-Vera is tied for second after catching fire on the back nine with three straight birdies beginning at the second hole (his 11th of the day.)
Lorenzo-Vera had a chance to take solo second but he made bogey on his final hole.
The 44-year-old Woods just made the cut by shooting a two-over 72 for an even-par 140.
Woods had two birdies on the back nine but finished with four bogeys in the round as he struggled with his new putter.
His playing partner, Northern Ireland’s Rory McIlroy, had a roller coaster round but also got into the weekend.
McIlroy made four birdies in a row starting at the seventh hole but then lost the momentum with a triple bogey on the par-four 12th.
McIlroy stepped up to the tee box on 12 at three under but walked off the green at even par after needing three putts.
McIlroy regrouped with a birdie on 16 and finished with one under 69. He is tied for 31st, seven strokes adrift of Li.