Quotable: "I usually got a good memory, I guess, so I take good notes and kind of remember what you want to do on each hole".
Mickelson claimed his first title since 2013 when he overcame compatriot and reigning PGA Tour Player of the Year Justin Thomas in a play-off last week.
Conners, who only made the field after another qualifier withdrew, leads the tournament after shooting a 4-under 67.
Tiger Woods gave himself a high grade after taming strong and gusty winds to trail first round Canadian leader Corey Conners by three strokes at the Valspar Championship in Florida on Thursday.
Northern Ireland's Rory McIlroy three-putted the 18th hole and finished at 3-over 74, his fifth consecutive round above par.
That left the former world No.1, who had spinal-fusion surgery last April and only returned to the PGA Tour this year, ahead of some other high-profile players competing this week, including world No.4 Jordan Spieth (76), four-times major victor Rory McIlroy (74) and Swede Henrik Stenson (74).
"I drove it well, hit a lot of good iron shots and had some good speed on the putts".
Among those joining Woods at one under were Masters champion Sergio Garcia and Adam Scott and English duo Justin Rose and Luke Donald, the 2012 victor. Woods slammed his wrists against a tree on the par-4 16th hole and let go of his club in the process.
One of the came at the par-3 fourth, when he was fooled by the wind and sent his tee shot sailing.
After clearing spectators, Woods placed his body against the tree and gave a mighty lash at the ball.
An 11ft putt for birdie on the 10th, followed by a smart four on the par-five 11th took him to within two shots of the lead.
Still, there was a lot to feel good about considering Woods remains a work in progress while returning from a fourth back surgery.
His short game was particularly impressive, nearly holing a flop shot from the rough at the par-five first, which led to a tap-in birdie and set a positive tone for the round. "I definitely like the challenge and like golf courses that put a premium on the fairway and hitting the green". Not too often in Florida do you find elevation.
On Woods, Mickelson added: "We've gotten pretty close over the last couple of years, with the team events and his great leadership that he's had as a vice-captain at the Ryder Cup, Presidents Cup". He had a Sunday crowd - in 50-degree weather and gusting winds - following his every move around the Copperhead course at Innisbrook.
We'll see if Woods can keep trending upward throughout Round 2 at the Copperhead Course with a live Friday blog.