The Australian world number one again took advantage of a receptive Stadium Course with very little rough and barely a breath of wind, recording birdies at the second, fourth, seventh, 13th and 14th to get to get to 14 under overall.
That put him three ahead of Ireland's Shane Lowry, who was the leader in the clubhouse at 11-under 133 after shooting a 68 that included an albatross two at the par-four 18th, where he holed out with a wedge from 120 yards in the fairway.
“It's not fun stopping and starting,” Day told Golf Channel after his round was disrupted for just over two hours due to the threat of lightning when he had completed just eight holes.
“I came back out not as sharp as I was this morning.”
Out in three-under 33, Day picked up further shots at the par-three 13th, where he drained a 40-foot putt, and at the par-four 14th, where his approach settled within three feet of the cup, to strengthen his grip at the top.
“I feel good about my game but the biggest thing for me is to focus on trying to extend the lead,” said the 28-year-old, who has long coveted a first Players title to add to his already impressive golfing resume.
“The moment that I lose a little bit of focus and make a few mental errors and mistakes, that's when I let the field back in.”
Jonas Blixt of Sweden (67), Germany's Alex Cejka (67) and American Cameron Tringale (69) were at 10 under while American Colt Knost and Rory McIlroy made the biggest moves of the day to finish at nine and eight under respectively.
Just 24 hours after Day became the fifth player to fire a record-low 63 at the event widely regarded as the most prestigious outside the four majors, American Knost followed suit with a 10-birdie display.
Knost had a chance to card a 62 and make history, but three-putted from long range on his final hole, the par-four 18th, for his only bogey.
Soon after, McIlroy was in good position to at least match Knost with a 63 as he teed off on his last hole, the par-five ninth, at nine under for the day but he wound up with a bogey to settle for a 64.
“I don't feel like I played that much differently today than I did yesterday but it's an eight-shot difference,” McIlroy said. “I'm in a good position even though I finished a little bit frustratingly, but these things happen.”
The cut was projected to fall at two-under 142 with defending champion Rickie Fowler (71) and world number two Jordan Spieth, also at one under after 14 holes, likely to miss out.
The second round will be completed on Saturday morning local time, with the third round to follow soon afterwards. – Reuters
Original source: Day stretches lead at Sawgrass