Leaderboard: Jason Day (-18), Daniel Berger (-13), Brendon Todd (-13), Kevin Na (-11), Jordan Spieth (-11), Justin Thomas (-10), George McNeill (-10), Scott Piercy (-10), Rory McIlroy (-9), Harris English (-9), Dustin Johnson (-9)
What it means: Day returned early in the morning to complete an opening-round 61, then kept right on going with his second round. Already with three wins since late July to his credit, and starting the week with the FedEx Cup lead, Day has another trophy in his sights - one that would bring with it the world No. 1 ranking. A closing bomb for eagle on No. 18 gave him a huge lead and a share of the PGA Tour's 36-hole scoring record.
Round of the day: Dustin Johnson was slow out of the gates, turning in an even-par 71 in the opening round, but he caught fire in Round 2. Johnson carded seven birdies before closing with an eagle on the par-5 18th. It all added up to a 9-under 62 and moved him inside the top 10 heading into the weekend.
Best of the rest: Todd has been steady this season after breaking through for his first win last year, and he is one of Day's closest pursuers after a second-round 63. Todd reeled off four birdies in a row on Nos. 2-5 en route to an outward 30, then spun back a wedge approach on No. 18 to close in style with an eagle.
Biggest disappointment: While many players feasted on lift, clean and place conditions, Bubba Watson was unable to back up an opening-round 65. Watson canceled five birdies with four bogeys, and his 1-under 70 made him the only player among the current top 25 who failed to shoot in the 60s.
Main storyline heading into Saturday: Who will stop Day? This tournament is far from over, but it certainly feels like the Aussie's to lose. He'll play the third round alongside Berger, a rookie who lost a playoff earlier this season at the Honda Classic, while Spieth lurks inside the top five - albeit seven shots behind the man with whom he played the first 36 holes.
Shot of the day: Day appeared poised for an easy two-putt birdie on the home hole, but his downhill eagle try from 43 feet was online the whole way. Day raised his putter as the ball found the bottom of the hole, eliciting a hearty cheer from the greenside gallery.
Quote of the day: "Those putts, you don't really expect to hole." - Day on his closing eagle putt