GLASGOW, Scotland - James Ward came from two sets down to beat John Isner in a Davis Cup match that lasted almost five hours on Friday, giving Britain a 2-0 lead over the United States in the first round.

The 111th-ranked Ward produced a big upset, clinching a 6-7 (4), 5-7, 6-3, 7-6 (3), 15-13 victory on his sixth match point against the 20th-ranked American at Emirates Arena in Glasgow. The match lasted 4 hours, 57 minutes.

When Isner sent a backhand volley into the net to end the longest U.S. Davis Cup match since the introduction of the tiebreaker in 1989, Ward threw his racket toward the net, pumped his chest and looked into the air. Then he hugged Britain captain Leon Smith, lapped up the applause of the crowd and stumbled over to teammate Andy Murray, who looked close to tears.

"I would prefer it if I didn't have to play these kind of matches every time," said Ward, who has won four of his five five-set matches in the Davis Cup.

Murray had it much easier Friday.

Britain's top player was impressive in beating Donald Young 6-1, 6-1, 4-6, 6-2 in his first match in his native Scotland since winning Wimbledon in 2013.

Britain is on course to beat the U.S. team for the second straight year at this stage in the World Group, after winning in San Diego in February 2014. Ward beat Sam Querrey if five sets in that series.

The British would clinch the match on Saturday if it wins the doubles, where Jamie Murray — Andy's older brother — and Dominic Inglot are scheduled to face Bob and Mike Bryan. Captains have until an hour before the match to make any changes, so there is still the possibility of a battle of the brothers between the Murrays and the Bryans.

The hard-serving Isner has a habit of playing long matches — few will ever forget his 11-hour win over Nicolas Mahut in the first round at Wimbledon in 2010, when the score in the final set was 70-68. There was no way he was going to last that long here.

The American struggled through the final games of a fifth set that lasted 111 minutes. He lost nearly every rally, with most of his points coming from aces or unreturnable serves.

He saved two match points in the 10th game, another in the 20th game, and two more in the 22nd. In the 28th game, though, Isner couldn't pull through, going down 0-40 and then missing the low volley.

Head bowed and with a towel around his neck, he was applauded off the court by the 7,700-capacity crowd.

The thunderous reception greeting Murray on his Scottish homecoming took him all the way back to the London Olympics in 2012, when he produced some of the best tennis of his career to win gold.

Murray, who was born in Glasgow, fed off the energy with the kind of performance he delivered on the lawns of Wimbledon two years ago. He made just one unforced error in the first two sets against Young, and dropped just five points in seven service games in that period.

"I played an extremely high level of tennis in the first two sets and it was tough to keep that intensity up," Murray said. "I had a lull in the third set and he managed to settle."

Young found his range with his forehand in the third set and broke Murray — for the only time — in the final game. Murray, though, quelled the American's comeback with a composed fourth set and a sliced-volley winner on his first match point was greeted with repeated fist pumps by the former Wimbledon and U.S. Open champion.

"You can't really prepare for that atmosphere. He played great," said Young, who arrived in Glasgow in form after reaching the semifinals in Memphis and the final in Delray Beach last month. "In the third set, he started to miss a little more and I loosened up but in the first two sets, I didn't make a dent."