SO inseparable have Phil Mickelson and Henrik Stenson become over the past 24 hours it would not come as a surprise to learn they also shared a bedroom last night like Sesame Street’s Bert and Ernie. Paired together on day three of the Open championship at Royal Troon, they will form the final group again this afternoon after delivering two impressively consistent rounds of golf that negated the threat of a relentless and often blustery wind that blew many of their rivals off course.

Stenson, looking to become the first Scandinavian man to win a Major, holds the upper hand going into the final round. Starting the day a shot behind Mickelson, the Swede stated his intent by making birdies on three of the first four holes. Bogeys on six and eight temporarily halted his progress but he came again on the back nine, picking up shots on the two par threes for a round of 68. A total of 12 under leaves him one shot better off than Mickelson with 18 holes left to play over which they will duel – Ryder Cup matchplay style – to find a winner.

“Phil is one of the best to play the game in the last 20 years and it's going to be a tough match,” said the Swede. “But I'm looking forward to the opportunity. I've worked hard these first three days to put myself in this situation and, once again, I’m going to try my hardest tomorrow to finish the job.”

Stenson came across remarkably relaxed for a man just one round away from perhaps fulfilling a lifelong ambition, even making a joke about the dreary local weather.

“I've put myself in a great spot. If you want to throw the odds if I give myself a 50-50 - it might happen, it might not happen. The sun will come up on Monday anyway, hopefully. Well, maybe not in Scotland.”

After leading after the first and second days, Mickelson was largely blemish-free on his third round too, enjoying bogey-free golf until the 14th hole. A dropped shot there and another on 17 saw the 2013 champion sign for a one-under round of 70, -11 for the tournament overall. He remains very much in contention for what would be a sixth major title.

“Today could have been a day that got away from me but instead I shot under par and kept myself right in heading into the final round, so I'm proud of that,” he said. “I was off today. I didn't have my best stuff. I'd love to play the final round the way I did the first two and give myself a shot.”

Mickelson had been less than enamoured with the work of a photographer clicking away on the 18th hole as he was making his approach shot to the green, his effort finding a bunker. “It’s so sh***y to do that,” he raged at the snapper. “I can't believe that. I get you've got to cover it but why interfere with it?"

With the Americans again having their tanks on Troon’s lawns as they look to provide a seventh successive champion here – seven of the top 12 on the leaderboard are from the United States – it was left to the unlikely figure of Andrew “Beef” Johnston to provide some sort of British resistance. Fast becoming a cult hero around the links, the bearded Englishman has manoeuvred himself to within seven shots of leader Stenson after shooting three under-par rounds. Among the many cheering him on as he made his way around the course was his rather emotional mother.

“When I chipped in on 13 I saw my mum was crying and I had to look away, man,” he said. “I was like, “oh my God. Don't look at my mum. Please, go over there”. But to have that reception [from the galleries] is amazing. I just love it. I really do.”

Rory McIlroy needed a fast start if he were to offer any kind of threat to the leaders but bogeys on the first and third holes sent him careering in the opposite direction, a setback from which he never recovered. The sight of the Northern Irishman breaking the head of his three wood after slamming it to the ground following another poor swing told the story of a frustrating afternoon.

“The club head came loose on it earlier on the week and I had to get it re-glued so it was probably partly to do with that and partly the throw as well,” he offered by way of explanation.