Phil Mickelson was the improbable leader of the 145th Open Championship at Royal Troon Golf Club in South Ayrshire, Scotland, when he walked off the course with a major championship record-tying 63 at 8-under on Thursday, and based on his own history in the event and historically sour conditions, only the brilliant weather was more surprising.
"I felt like it was kind of easy. I didn't try to do too much," Mickelson said following the round. "We had the most amazing day today. I haven't seen weather like this in 11 days being over here. ... I took advantage of it. It was fun."
It was the ninth round of 63 in the Open Championship and fractions short of a more historic round of 62.
"It's heartbreaking. I'm not going to have a chance to do something historical like that again," Mickelson said after his putt on 18 lipped out.
Mickelson approached the 441-yard 18th hole with a shot at a major tournament record 62.
He missed the fairway left off the tee, narrowly hurdling a bunker.
His second shot from 179 yards landed softly on the center of the green and he walked with Ernie Els up the fairway with a full smile to the roaring applause normally reserved for Sunday's leader pacing to claim the Claret Jug.
Els two-putted and finished the round even to clear the green for Mickelson's historic 16-foot putt which rode the right lip around and out, similar to Tiger Woods' circling putt for the major-championship record 62 in the 2007 PGA Championship.
"Did you see that ball at the end? It was centered," Mickelson said walking off the green to sign his scorecard.
Mickelson played fairway to green most of the round and fired a 32 on the front nine with four birdies.
By the time he made the turn, Mickelson was chasing Patrick Reed -- already in the clubhouse with an early 66.
Mickelson drained a 16-foot birdie putt on the par-3 14th to take sole possession of the lead at 6-under par. He birdied the par-5 16th and tied his personal best with an eighth birdie on No. 17, this after a par at 15.
Mickelson was bogey-free and was under par on the course for the fourth consecutive round. He finished third in the last Open played at Royal Troon (2004).
Thursday's round was the best for Mickelson in the Open since he shot 6-under 66 in the second round of the 2000 Open at St. Andrews.
Near-passing trains and cargo planes were the only distractions Mickelson acknowledged on a windless 70-degree day Thursday. The second round could bring a brand new course as temperatures drop, precipitation hits and wind speeds are likely to be more typical of Scottish links golf, gusting to further tighten the narrow fairways and unfriendly greens that bring a challenge to every shot at Royal Troon.
Defending champion Zach Johnson, who was in the top three in total putts and greens in regulation at the 2015 Open Championship, was 5-under through 15 as Mickelson finished.
Billy Horschel was part of a group at 4-under par - Americans Steve Stricker, Justin Thomas and Tony Finau among them -- and scores across the board were lower than the typical Open Championship.
"It's really good -- I'll take it the next two days if you want to give it to me," Horschel said. "We're just trying to make sure our strategy for those back nine holes, we're conservative, have a really good game plan for this golf course."