One year after winning the Scottish Open in a playoff at Castle Stuart, Mickelson opened his title defense with a 3-under 68 at Royal Aberdeen to grab a spot on the early leaderboard, four shots behind Rory McIlroy.
"I was surprised to see some of those low scores out there because it didn't seem like it was playing easy and the wind was pretty strong and the fairways were tight," Mickelson told reporters. "But I felt like I played well, and had a good putting day and it was a good day."
Mickelson began his round with five consecutive pars before an eagle on the par-5 sixth hole. He added back-to-back birdies on Nos. 12 and 13 to highlight his inward half. His lone blemish of the day came on the 18th hole, when he raced his 20-foot birdie attempt 4 feet past the hole and failed to make the short comeback putt for par.
Mickelson makes birdie from the cart path on par-4 13th in Round 1
The 44-year-old notably does not have a top-10 finish on the PGA Tour this season, though he did tie for second at the Abu Dhabi HSBC Golf Championship on the European Tour in January. He is teeing it up for the first time since his bid for the career Grand Slam ended with a tie for 28th at the U.S. Open at Pinehurst.
Last year's Scottish Open title was Mickelson's first victory in Europe in 20 years, and the following week he became the first player to win both the Scottish Open and the Open Championship in the same year when he claimed the claret jug at nearby Muirfield.