Li Haotong will take a surprise two-stroke lead into the weekend at the US PGA Championship after an impressive second round.

The 25-year-old is bidding to become the first Chinese man to win a major and is well-placed at TPC Harding Park in San Francisco.

Li backed up his opening-round 67 with a five-under 65, moving to eight under and into a two-shot lead.

He produced a bogey-free round that featured five birdies to sit clear of Brooks Koepka (68), Jason Day (69), Tommy Fleetwood (64), Daniel Berger (67), Justin Rose (68) and Mike Lorenzo-Vera (68).

Koepka's bid for a third straight US PGA title remains well and truly alive despite the American needing treatment on his hip during his second round.

The four-time major champion birdied his final hole to be in the six-way tie for second on what remains a congested leaderboard.

A closing birdie for @BKoepka.

He's two back heading into the weekend in search of his third straight @PGAChampionship. pic.twitter.com/T8E3OWqlPT
— PGA TOUR (@PGATOUR) August 8, 2020

Day, who shared the overnight lead with Brendon Todd (70), was among those challenged in the tougher conditions later in the day.

But none of that group could catch Li, who spent hours practising after his round was over.

The leader by THREE.

Everyone at @TPCHardingPark is chasing @haotong_li. pic.twitter.com/TSymnatYcH
— PGA TOUR (@PGATOUR) August 7, 2020

Todd, Paul Casey (67) and Cameron Champ (64) are tied for eighth at five under, while several big names have endured a mixed start to the tournament.

Dustin Johnson continued his consistent start with a 67 to be at four under, alongside the likes of Xander Schauffele (70).

The likes of Tiger Woods, Rory McIlroy, Jordan Spieth and Justin Thomas, though, were at risk of missing the cut.

While Woods (72) never got going, McIlroy (69) got on a roll that included four straight birdies before undoing his good work at the 12th, where he made a triple bogey after finding the rough.

Back-to-back birdies for Rory. #PGAChamp pic.twitter.com/P6fVjn1YWc
— PGA Championship (@PGAChampionship) August 7, 2020

Woods and McIlroy are even and one under respectively, while Spieth (68) and Thomas (70) made the cut by a stroke, sitting at one over.

Rickie Fowler, meanwhile, saw his run of 14 consecutive majors without missing the cut end after following up his 73 with a 69.

While Sergio Garcia also missed the cut, 2010 champion Martin Kaymer failed to reach the weekend, shooting a 12-over 82 a day after his opening 66.

Meanwhile, Cameron Tringale was disqualified from the event for the second time after signing an incorrect scorecard.