He birdied 16 by sinking a 10-footer and survived a scare at the 230-yard par-3 17.
His ball landed some 40 feet short of the pin, took a huge first bounce and finally clattered against the bottom of the flagstick on the fifth bounce. Day was unlucky not to make a hole-in-one, but the stick also saved his ball from rolling off the back of the green.
The 30-year-old was feeling it, too.
The last time Woods and Mickelson played together at the Players was 2001, when Woods won the first of his two titles at the event.
Woods was rated among the favourites at the U.S. Masters in April, but finished equal 32nd and blamed poor iron play.
Woods carded a birdie-free 74 on Sunday to finish in a tie for 55th place at Quail Hollow in Charlotte, N.C.
The 14-times major champion said he would work on all facets of his game before the Players Championship starts in Florida on Thursday at TPC Sawgrass, where he has won twice. "So I went up vertically and used the side of the rock to kind of get it to go to the right".
"You're your own worst enemy out there, especially today", Day said. His tee shot on the par-3 hit the flag and stopped just three feet from the cup.
"That was awesome to watch this morning, so hopefully I can just pass that along in my game". "I missed a lot of fairways, missed a lot of greens".
"I said earlier I was fighting demons out there because when you're not hitting it good, it just feels like the life is getting sucked out of you", he said.
It is only two years since Day dominated the game, but he lost his way a bit last year, his first winless season since 2013, while dealing with his mother's cancer diagnosis and symptoms of burnout.
The best evidence of this is the fact that Phil Mickelson, a World Golf Hall of Fame player with a five-pack of major championships, has never held the No. 1 ranking and, if he's being honest, probably doesn't feel like it's a glaring hole in his resume.
"Me and my caddie actually talked about it", Wise said, per Golf Channel's Rex Hoggard.
"You've got to give a lot of time to a lot of people and sometimes you don't get a lot of time to yourself".
"To have the opportunity to come out here and enjoy it, have a great week". "I know the feeling and what it felt like to be No. 1 and I know what I had to do to get there".