Andy Murray seals Davis Cup 2015 quarter-final place for Great Britain

Andy Murray sealed a Davis Cup quarter-final place for Great Britain with a straight-sets win over American John Isner in Glasgow.

He saved three set points in the first set and won 7-6 (7-4) 6-3 7-6 (7-4) to give Britain an unassailable 3-1 lead in the World Group first-round tie.

Britain will next play France at home in July, with the venue to be decided.

"It feels great. This is a team effort and I think everyone agrees the team played their part," said the Scot.

Murray, 27, who returned to play in Scotland this week for the first time in four years, looked edgy in the early stages against Isner but was clinical when it counted.

"On behalf of all of the players I want to thank the crowd because it's been one of the most special atmospheres I've ever played in," he added.

Togetherness key to win - Murray

Murray had been a heavy favourite to finish the job for Britain against a player who had suffered a "brutal" five-set defeat by James Ward on Friday.

It is the second year running that Britain have beaten the United States, and Isner said: "This one's on me.

"My team-mates may say otherwise but when you look at this match-up on paper, my loss on Friday put us in a huge hole.

"It's so, so disappointing for me. I feel like I let us down this week. It's a terrible feeling."

BBC Tennis Correspondent Russell Fuller "Isner looked anything but a player detained on court for nearly five hours on Friday in the opening set - hitting the ball with aggression and ambition, and forcing Murray to play several clutch points to stay in contention. There was a sense of inevitability once Murray broke the Isner serve midway through the second set, but - thanks to the crowd - never a sense of anti-climax. France may have seven players in the top 40 but they can expect a feisty welcome whichever venue is chosen to stage July's quarter-final."

Isner began the better, however, earning seven break points - three of them set points - before Murray finally fashioned his first after 86 minutes.

A double fault from Isner at the start of the tie-break proved the decisive moment in the first set, but he had already wasted two inviting forehands on set points.

Murray's previously shaky serve found its range as he closed out the set efficiently, much to the relief of most of the 7,700 spectators.

It seemed inevitable that Isner's challenge would fade after his exertions of 48 hours earlier but it took a moment of brilliance from Murray to get the better of his huge serve.

After some loose Isner forehands offered the Briton his first break point of the day, Murray sent up a brilliant lob that had the 6ft 10in American scrambling in vain.

While Isner was predictably leading the ace count, it was the steadily rising number of unforced errors that was now more significant as Murray saw out the set and pushed hard early in the third.

Isner served his way out of a seemingly desperate situation at 0-40 and got within two points of the set at 5-4, 0-30, but Murray snuffed out the danger.

Another early break in the tie-break helped the Scot to a 6-2 lead and he converted his third match point with an ace, drawing a deafening roar from the home crowd.

Asked about the prospect of facing France at home the week after Wimbledon, Murray said: "I would imagine we'd try to play that on a grass court possibly.

"I don't know how many grass courts they have here in Glasgow but if they can lay one, I'd really love to play here again."

Ward played the final dead rubber against Donald Young but retired after winning the first set to protect a sore knee, as he will fly to Indian Wells with Murray on Monday, so the tie ended in a 3-2 win for Britain.