|US Open round four|
|Date: Sunday, 20 September|
|Coverage: Live text commentary on BBC Sport website from 18:00 BST. Live commentary on BBC Radio 5 live Sports Extra 20:00|
|US Open third-round leaderboard|
|-5 M Wolff (US); -3 B DeChambeau (US); -1 L Oosthuizen (SA); Level H Matsuyama (Jpn), X Schauffele (US); +1 R McIlroy (NI)|
|Selected others: +3 P Reed (US); +4 J Thomas (US); +5 P Casey (Eng), D Johnson (US), L Westwood (Eng); +7 J Rahm (Spa); +8 M Wallace (Eng); +12 R MacIntyre (Sco); +13 S Lowry (Ire)|
Matthew Wolff takes a two-shot lead into the final round at Winged Foot as he looks to become the first debutant in 107 years to win the US Open.
The American, 21, had six birdies in a scintillating five-under 65 to improve to five under par overall in New York.
Bryson DeChambeau is three under, with Louis Oosthuizen at one under.
Northern Ireland's Rory McIlroy is in contention at one over after "a good round" of 68 - one of only seven players to shoot under par on Saturday.
The world number four, who finished a couple of hours before Wolff, said he felt he would have a chance on the final day if he could stay within six of the lead.
"The key for me was just to play the first five holes well. I saw from a few of the guys early on those holes were playing really tough," said McIlroy, after a round containing three birdies and one bogey.
"I knew that middle section of the round you could maybe make a couple of birdies and then you sort of have to hang on coming in.
"I executed the game plan really well, knocked a couple in when I could. It was a really good round of golf."
Wolff, playing in only his second major after qualifying for this tournament by tying for fourth at last month's US PGA Championship, holed five birdies as he played the first nine holes in 30 shots.
The world number 36, who has one win on the PGA Tour, only hit two of 14 fairways but scrambled well and made just one bogey, after finding the trees on the 16th with one of many wayward tee shots, but recovered to birdie the last.
"I got pretty fortunate with my lies in the rough," he said. "I stuck with my game. It was a grind out there but hopefully I will hit a few more fairways on Sunday."
If Wolff completes the win, it will be 107 years, to the day, since 20-year-old amateur Francis Ouimet claimed the title at his first attempt after winning a US Open that had also been delayed from June to September.
This year's was pushed back because of the coronavirus pandemic. Back then, it was to allow six-time Open champion Harry Vardon and fellow Briton Ted Ray to play. Ouimet, who famously had a 10-year-old caddie, beat them both in an 18-hole play-off.
Wolff would also become the youngest man to win a major since Tiger Woods claimed the first of his 15 at the 1997 Masters.
His closest challenger is DeChambeau, who looked set to post a third successive round in the 60s after birdies on 16 and 17 but he bogeyed the 18th to hand Wolff a two-stroke advantage at the top.
The world number nine, chasing his first major title, was satisfied with his level-par round after beginning the day with successive bogeys.
"It shows perseverance and resilience," said DeChambeau, who added he was heading to the practice range to "fix a couple of things".
Reed crumbles after extending lead
Only three players enter the final day under par, though Japan's Hideki Matsuyama and American Xander Schauffele both briefly made charges on Saturday.
Matsuyama is trying to become his country's first major winner and he climbed to three under, only to bogey the 15th and then double-bogey the 17th to drop back to level for the championship.
He will head out in the penultimate group on Sunday alongside South Africa's Oosthuizen, who tied for second in this tournament in 2015.
The former Open champion is four off the pace after a third-round 68 that included four birdies and two bogeys.
Schauffele, meanwhile, rolled in for an eagle at the par-five ninth to move to two under before three bogeys after the turn, although he finished with a birdie to also sit level.
Overnight leader Reed started with a one-stroke lead and stretched that advantage to three with a birdie at the second as his nearest challengers faded away.
But Wolff's electric start meant that by the time Reed walked off the third green with a bogey, his advantage had been wiped out.
The American Ryder Cup player was one under for the day as he hit the turn but soon fell away with six dropped shots in six holes on the back nine, including a double bogey at 11 after fluffing a chip that failed to escape the rough.
The 2018 Masters champion finished with two bogeys to sign for a seven-over 77 that leaves him three over par and eight shots off the lead.
Conditions remained tough on Winged Foot's West course, where Geoff Ogilvy won at five over when it last staged the US Open in 2006.
Paul Casey was one of the seven to shoot under par, with a one-under 69 taking him to five over, alongside fellow Englishman Lee Westwood and world number one Dustin Johnson.
Casey slumped to 11 over par after five bogeys in his first seven holes, but birdied the ninth and made five more on the back nine.
"In all honesty I kind of wanted to walk in after the first five, six, seven holes. It was just ugly," said the 43-year-old. "I was just trying not to shoot 80 after that front nine. I'm glad I finally got one off of Winged Foot.
"It takes its pound of flesh every single time you seem to play this golf course, so I feel like I got an ounce or two of my own flesh back."
- Kitchen Starter Pack: Delicious recipes and food hacks that won't break the bank
- BBC Food: How well do you know your coffee?