Henrik Stenson holds a one-shot lead over Phil Mickelson at the British Open

Phil Mickelson and Henrik Stenson are hardly enemies, but even friends would be getting sick of each other by now with the time the two have spent together this year.

By Stenson’s count, they’ve been paired together in the Masters, U.S. Open, Players Championship and just last week in the Scottish Open.

They were shackled again on Saturday in the third round of the British Open, still couldn’t shake loose and were set for one very important rematch on Sunday at Royal Troon.

In all likelihood, the guy who captures this particular match will lift the Claret Jug.

“There’s only one thing that matters,” Stenson said. “I know he’s not going to back down, and I’m certainly going to try to not back either. So it should be an exciting afternoon.”

On the strength of a two-shot swing on the par-3 17th hole in Saturday’s round, Stenson took a one-shot lead at 12 under after 54 holes. In shooting 3-under 68 amid intermittent showers and constant wind, the Swede gained two shots for the day on Mickelson, who lost his tempo after two stellar rounds, but scrambled to pull himself together for a hard-fought 70.

Though it’s silly to call anything match play in a stroke-play tournament – especially with the crazy things that can happen in a major – this might come as close as it gets.

It seems miles to the next-closest pursuers. Bill Haas (69) was in third, six off Stenson’s lead. Popular Englishman Andrew “Beef” Johnston (70) was seven back and J.B. Holmes (69) was eight behind.

It’s proof of how impressively Mickelson and Stenson have played.

After the round, Mickelson quickly shook off any suggestion that this would be match play between two Ryder Cup rivals, but Stenson seemed to embrace it. Maybe those who’ve lost remember the past more. Stenson was among a group three years ago who were overtaken by Mickelson’s blazing final stretch as he shot 66 to win his first British Open.

“There’s always revenge,” Stenson said with a smile.

“Yeah, it would be great to hand one back to him tomorrow, absolutely. But as we know it’s going to take some good golfing to do that, but I’m certainly willing to give it a try.”

Phil Mickelson plays from a green-side bunker during the third round of the British Open at Royal Troon on July 16.

(Glyn Kirk / Getty Images )

Between the two, there are very different career paths coming to a crossroads.

Mickelson, 46, whose golfing legacy is all but secured except for winning the U.S. Open, is trying to seize his second Open victory in four years and grab a sixth major title to tie him with Nick Faldo and Lee Trevino.

The San Diegan, who has dropped to 19th in the world rankings, hasn’t won since the British in2013.

Stenson, 40, has never played in the final group in a major, is considered something of a career underachiever, and has the added pressure of trying to capture his first major.

Ranked sixth in the world, Stenson’s last win came last month in the European Tour’s BMW International Open.

“I think I potentially played better here this week than I did when I won in Germany,” Stenson said. “But it just keeps on reminding you’ve that you’ve got to stick to your game, hit your shots and do all the right things, and hopefully the outcome will come your way.”

Mickelson looked supremely confident in his first two rounds, seemingly hitting most shots at will in scoring 63-69. But he admitted to pressing early on the front nine on Saturday, and he got quick with his swing.

He said he and coach Andrew Getson, who had been here all week, had some work to do to get him back on track.

“I didn’t have my best stuff,” Mickelson said. “.. I was a little jumpy and my rhythm wasn’t very good today. I found a way to kind of settle in and hit some shots, and then find ways to make pars on the times that I hit poor shots.”

Mickelson made some impressive pars from bad spots -- the best coming at the par-4 12th. He sprayed his 2-iron, a reliable club this week, to the left off the tee and got a break when it stayed out of a gorse bush. He didn’t have a full backswing, but managed to punch the ball back onto the fairway. He watched his third shot trickle off a backboard area of the green to 12 feet and made the putt.

He produced a small fist pump there and a bigger one at 13 when he rolled in a birdie to take a two-shot lead.

But Mickelson gave one shot back with a three-putt bogey at 14 and was on the wrong end of a two-shot swing at 17. Mickelson missed the green at the par-3 and made bogey, while Stenson hit a great tee shot and drained an 8-footer for birdie.

“The one on 17 certainly put me in front and gave me that little edge going into tomorrow,” Stenson said. “I’ve always thought that it’s better to be one ahead than one behind, because that means Phil’s got to play better than I do.”

Stenson figured his chances to win at 50-50.

“It might happen, it might not happen,” he said. “The sun will come up on Monday anyway, hopefully. Maybe not in Scotland, but other parts of the world.”