Augusta - Five-time major winner Phil Mickelson birdied five of the last seven holes in Thursday's opening round of the Masters, leaping into contention to become golf's oldest-ever major champion.
The 48-year-old American left-hander fired a five-under par 67 at Augusta National to stand one stroke behind US co-leaders Brooks Koepka and Bryson DeChambeau after 18 holes.
"It's fun to finish a good round off rather than leak one here or there coming in. So it was a good day," Mickelson said.
"It was great. It was a lot of fun."
Mickelson, a three-time Masters champion who turns 49 in June, could surpass the major age win record owned by Julius Boros from the 1968 PGA Championship and the Masters mark of 46 by Jack Nicklaus in 1986.
More importantly for Mickelson would be a fourth green jacket to match Tiger Woods and Arnold Palmer for second on the all-time list behind the six of Jack Nicklaus.
Mickelson considered it important to take full advantage of a course softened by rain.
"I was just hoping to shoot in the 60s. I thought there were some 66s out there," Mickelson said.
"Look, the greens are softer than they've ever been, and they're not as fast as they normally are. So today was a day to take advantage of it. I'm sure they'll get firmer and faster as the week goes on. But you could get after the pins and you could putt aggressively."
Mickelson birdied the par-5 second and eighth holes but opened the back nine with back-to-back bogeys. Instead of stumbling, Mickelson saw the setbacks as momentum savers.
"It looked like after bogeying 10 and 11 that would kill some momentum," Mickelson said.
"It was the other way around, because I made two great bogeys that should have and could have been doubles.
"After going in the water at 11 to hit that close and have an easy bogey and then to make a 6-footer for bogey on 10 after a terrible drive, those were almost momentum maintainers, if you will, that kept me in it.
"And then when I got to the holes that I could birdie I took advantage of it with some good shots."
Mickelson torched Amen Corner for birdies at the par-3 12th and par-5 13th, birdied the par-5 15th and par-3 16th, then salvaged par at 17 from eight feet before closing with a birdie.
"It was fun to make a good par save on 17 and birdie the last," he said.
"I ended up getting up and down, making about a seven or eight footer for par, and that was a great momentum builder for me to finish off the round."
Scores after Thursday's opening round of the 83rd Masters tournament at par-72 Augusta National Golf Club:
66 - Bryson DeChambeau (USA), Brooks Koepka (USA)
67 - Phil Mickelson (USA)
68 - Ian Poulter (ENG), Dustin Johnson (USA)
69 - Justin Harding (RSA), Adam Scott (AUS), Jon Rahm (ESP), Kevin Kisner (USA), Kiradech Aphibarnrat (THA)
70 - Corey Conners (CAN), J.B. Holmes (USA), Lucas Bjerregaard (DEN), Gary Woodland (USA), Tiger Woods (USA), Rickie Fowler (USA), Cameron Smith (AUS), Patton Kizzire (USA), Francesco Molinari (ITA), Jason Day (AUS)
71 - Tony Finau (USA), Charley Hoffman (USA), Louis Oosthuizen (RSA), Tommy Fleetwood (ENG), Kevin Na (USA), Thorbjorn Olesen (DEN), Bernhard Langer (GER), Matt Kuchar (USA)
72 - Andrew Landry (USA), Keith Mitchell (USA), Kevin Tway (USA), Mike Weir (CAN), Kim Si-woo (KOR), Branden Grace (RSA), Emiliano Grillo (ARG), Kyle Stanley (USA), Webb Simpson (USA), Viktor Hovland (NOR), Marc Leishman (AUS), Li Haotong (CHN), Jimmy Walker (USA), Billy Horschel (USA), Bubba Watson (USA)
73 - Takumi Kanaya (JPN), Charles Howell (USA), Sergio Garcia (ESP), Patrick Reed (USA), Xander Schauffele (USA), Rory McIlroy (NIR), Sandy Lyle (SCO), Martin Kaymer (GER), Alvaro Ortiz (MEX), Jovan Rebula (RSA), Rafa Cabrera Bello (ESP), Tyrrell Hatton (ENG), Patrick Cantlay (USA), Justin Thomas (USA)
74 - Eddie Pepperell (ENG), Henrik Stenson (SWE), Trevor Immelman (RSA), Devon Bling (USA), Zach Johnson (USA)
75 - Adam Long (USA), Aaron Wise (USA), Danny Willett (ENG), Brandt Snedeker (USA), Hideki Matsuyama (JPN), Matt Wallace (ENG), Alex Noren (SWE), Satoshi Kodaira (JPN), Justin Rose (ENG), Jordan Spieth (USA)
76 - Michael Kim (USA), Stewart Cink (USA), Keegan Bradley (USA), Shugo Imahira (JPN)
77 - Kevin O'Connell (USA), Charl Schwartzel (RSA), Larry Mize (USA)
78 - Shane Lowry (IRL), Fred Couples (USA), Jose Maria Olazabal (ESP), Matthew Fitzpatrick (ENG)
80 - Ian Woosnam (WAL), Vijay Singh (FIJ)
81 - Paul Casey (ENG)
82 - Angel Cabrera (ARG)