Juan Martin Del Potro led Argentina to an opening day lead over Great Britain in the semi-final of the Davis Cup after beating Andy Murray in a five set epic.

Britain, who are bidding to defend the title that they won in Belgium last year, were the favourites ahead of this weekend’s tie in Glasgow but now need to win all three remaining matches to reach the final following Kyle Edmund’s defeat to Guido Pella in the second singles match.

Del Potro’s match with Murray was eagerly anticipated following their memorable clash in the final of the Olympics last month and it certainly lived up to its billing.

After a pulsating five hours and five minutes it was the Argentine, with his towering serve and sledgehammer forehand, who finally prevailed 6-4 5-7 6-7 (5-7) 6-3 6-4 in a gripping contest.

Rare Davis Cup defeat for Murray

The British number one hit 35 aces but was unable to stop the Del Potro siege, eventually succumbing to just his third singles defeat in Davis Cup and his first on home soil.

"I think it was good match. I felt there wasn't too many mistakes on important moments,” said Murray after the result.

"Both of us came up with good stuff and the shot he came up with to break in the fifth set was the difference,” he added.

A packed out Emirates Arena were treated to an all-time classic as both men once again demonstrated the passion and desire which comes with playing for your country.

Del Potro back to his best

After splitting the first two sets, Murray was able to edge a third set tie break following a series of prolonged and exhausting rallies from the baseline.

Even so Del Potro, renowned for his huge forehand, was rock-solid from the back of the court all match and came up with a quick riposte to take to fourth.

The Argentine’s level only improved in the decider, as he broke Murray early in the set and was able to maintain his advantage despite the Brit’s resilience.

An elated Del Porto said afterwards: "I won but I still remember the Olympic final. This is very important to me and my team and we are looking to reach another final in the Davis Cup."

He continued, "Against Andy you never know when the match will finish. He is a dangerous player, a fighter and great champion. In end I played good forehands and good serves and that was key."

Edmund falls to Pella

That result abruptly swung the tie in Argentina’s favour and shifted the pressure onto Edmund ahead of his clash with Pella- the world number 49.

The Brit, who has recently reached a career high of 55 in the world, made an impressive start, taking the opening set on a tie break.

Even so his higher opponent fought back to claim a 6-7 (5-7) 6-4 6-3 6-2 victory and put Argentina 2-0 ahead of tomorrow’s doubles rubber.

Murray is expected to play alongside his brother Jamie in a match that Britain have to win to keep the tie alive.