TROON, Scotland (AP) -- Henrik Stenson and Phil Mickelson delivered what everyone expects out of a major championship.
They matched birdies and improbable par saves. Momentum could change with any shot. The lead changed four times over four hours of golf at its highest level, played in the cold wind and occasional rain off the Irish Sea. All the British Open lacked Saturday was a winner.
Turns out this was only the preview to a duel at Royal Troon.
Stenson took the lead for the last time with another two-shot swing on an inward par 3, and he kept it with a nifty up-and-down on the 18th for par and a 3-under 68, the second straight day that no one had a better score.
That gave the 40-year-old Swede his first lead in a major, even if it was just one shot over someone who already has five majors and his name on the claret jug.
"There's only one thing that matters tomorrow," Stenson said. "I know he's not going to back down, and I'm certainly going to try to not back down, either. So it should be an exciting afternoon. ... I've worked hard these first three days to put myself in this situation and I'm going to try my hardest tomorrow to finish the job."
Links golf can deliver some strange finishes, though this had all the trappings of a two-man race on Sunday.
Stenson had his third straight round in the 60s - no one has ever won at Royal Troon with all four rounds in the 60s - and was at 12-under 201. He is trying to become only the eighth player dating to Old Tom Morris in 1861 to win his first major after turning 40.
Mickelson, winless since he lifted golf's oldest trophy at Muirfield three years ago, had a 70. His game was nowhere near as sharp as his opening-round 63 that tied a major championship record. Even so, he came up with the rights shots at the right time until Stenson passed him late in the afternoon.
"Some days it's easy and it looks pretty like the first couple," Mickelson said. "Some days it's hard and it looks terrible, like it did today. But either way, I shot three rounds under par."
He made a 25-foot birdie putt on the 13th hole for a two-shot lead. Stenson answered with a 5-iron to 6 feet for birdie on the next hole to tie for the lead when Mickelson three-putted, only his third bogey of the week.
Mickelson regained the lead with a pitch to 4 feet for birdie on the par-5 16th, only for the Swede to answer again, this time with an all-out 3-iron into the wind on the 220-yard 17th hole to 20 feet. Mickelson lost the lead by missing the green to the left and making bogey.
Everyone else felt like mere spectators.
Bill Haas, a seven-time winner on the PGA Tour who is rarely heard from at majors, was solid with a 69 and alone in third. It's his highest position ever in a major, yet he was six shots off the lead. Another shot back was Andrew Johnston, the Englishman with a big belly and beard to match who goes by "Beef." He broke par for the third straight day with a 70.
It was unlikely to matter.
This was all about Stenson and Mickelson, two powerful players with different styles and different credentials, mainly the number of majors - five for Mickelson, none for Stenson. Mickelson spoke earlier in the week about not having as much pressure knowing he already has won them.
Not since Davis Love III and Justin Leonard shared the lead and were seven shots clear of the field in the 1997 PGA Championship has the final round of a major took on the appearance of match play.
"I was happy enough to throw two good punches in there on the par 3s and pick up two shots on either one of them to come back out on top at the end of the third round," Stenson said. "I've always been of the thought that it's better to be one ahead than one behind, because that means Phil's got to play better than I do."
Mickelson finished three shots ahead of Stenson three years ago at Muirfield when Lefty closed with a 66 in one of the best final rounds of a major. He hasn't won another tournament since, and at age 46, it appeared time was running out.
A victory Sunday would give him six majors, same as Nick Faldo and Lee Trevino. He also would be the third-oldest major champion behind Julius Boros (48) and Morris, with whom Mickelson shares a birthday - June 16, albeit 149 years apart. The 1861 Open was played in September.
Stenson was on the verge of falling two shots behind until he holed a 40-foot par putt on the 10th. Two holes later, Mickelson was in danger of losing the lead when he pushed his 2-iron toward trouble and was fortunate the ball deflected off a piece of prickly gorse. He had just enough room to hammer it up the fairway, and then played a shot rarely seen in links golf - instead of running it up along the ground, he spun it back down a ridge to 6 feet for a key par.
"I got lucky that that ball didn't go into the gorse, even though I didn't have a back swing," Mickelson said. "I still had a chance to advance it a little bit. I still hit a good shot to advance it down the fairway like I did, and found a way to get up and down."
Now, they have one more round, this time with a claret jug at stake.