Jason Day tied the United States PGA Tour's 36-hole record low and maintained his iron-clad grip on the BMW Championship at Conway Farms in Chicago today.
After starting the second day at 10-under par through 17 holes, the opening round having been halted by bad weather, the Queenslander made a solid par for a career-best 61.
Then he followed up with a brilliant 63, putting the exclamation mark on his round with a long, bombed eagle putt from 13 metres at the par-five 18th. It extended his lead in the third of the PGA Tour's four playoff events to five shots with two rounds to play.
Day, the world No. 3, will reach a world No. 1 ranking for the first time if he wins this week. At 124, he has never gone so low through 36 holes and nor has anyone gone lower in a tour event. He joins Pat Perez (2009 Bob Hope Classic) and David Toms (theColonial in 2011) at that landmark.
His Thursday 61 was his lowest as a professional; his only lower round anywhere was as a 13-year-old, at Mt Morgan Country Club in Queensland around the time he began aspiring to be the best player on the planet.
Day, who has already won four tournaments including his first major title this year, was peerless today.
His only challenger was rookie tour player Daniel Berger, who grabbed a share of the lead when he got hot early on the back nine. But just as soon as that occurred, Berger lost a ball on the par-five 14th and made bogey, and Day surged again.
He made good saves at the par-four 15th and 16th, including a wicked flop shot from a downslope and over a trap at the 15th, arguably his shot of the day. Mostly though he launched outrageous tee shots into the sodden fairways, where the professionals were allowed to lift, clean and place.
His only real mistake came at the par-four 13th, where his tee shot found thick rough and his approach squirted into the greenside bunker on the right, from where he left his par putt on the lip.
But more typical were the two towering shots he hit at the 18th, giving himself a long, downhill eagle putt that tracked all the way to the hole and into the cup, complete with a fist pump. "Those putts;, you don't really expect to hole,'' he said later. "I'm going to try and hole it, but at the end of the day, I got it on a really nice line. Rickie (playing partner Rickie Fowler) came over to me and said 'I called you were going to hole that'. I wish he could call all my shots for the next two days.''
Day was shocked to go so low immediately after his opening 61.
"Just free,'' was how he described his feeling over the past two days. "That's one word I can describe it (with). I just get up there and … I backed off a few shots today. I'm sure everyone saw it at home. Those are the times you need to because I was not having positive thoughts on those, and I hit good shots after those back-offs.''
Americans Berger and Brendan Todd are his closest challengers with two rounds to play. World No. 2 Jordan Spieth (11-under) is spotting Day seven shots over the weekend.
Of the other Australians, Steven Bowditch is tied-29th and still projected to reach next week's Tour Championship, while Matt Jones (T38) is just outside.