American Scottie Scheffler secured his place in the history books with a brilliant round of 59 in the Northern Trust at TPC Boston.
Scheffler carded 12 birdies and no bogeys on the par-71 layout to reach 13 under par and share the early clubhouse lead with Australian Cameron Davis in the first FedEx Cup play-off event.
The 24-year-old from Texas, who finished in a tie for fourth in the US PGA Championship earlier this month, is the 12th player to break 60 on the PGA Tour, with six of those rounds coming since 2016.
Scheffler birdied the second, added four more in a row from the fourth and picked up another shot on the ninth to race to the turn in 30.
Further gains on the 10th, 11th, 14th, 15th and 16th left him needing to birdie the par-five 18th to break the 60 barrier and he calmly two-putted from around 80 feet from just short of the green.
Speaking after his round, Scheffler said: "Today was obviously a good day on the course. I got off to a really good start, made a bunch of birdies on the front nine.
"I had some key up and downs at the beginning of the round that kind of got me rolling, freed me up a little bit. Then the momentum just kind of kept going. I never really lost momentum, which was nice."
Scheffler admitted it was strange to shoot an historic round without any spectators, adding: "To be completely honest, there was nobody out there watching our group until I think 17 (when) some cameras showed up. So we were pretty much just out there having fun, hanging out.
"You don't ever really get too many opportunities to shoot a 59, so to be able to finish the job is really cool, and I definitely was nervous, very nervous over both those shots (putts on 18) and coming down the stretch, but I think it helped me focus a little bit more."