Juan Martin del Potro has given Argentina a 1-0 advantage in their Davis Cup semi-final with Great Britain after emerging victorious from an epic encounter with Andy Murray.

In a match which lasted five hour and seven minutes - the longest of Murray's career - Del Potro finished strongly to win 6-4 5-7 6-7 6-3 6-4 in front of a captivated crowd in Glasgow.

The opening stages of the contest set the tone for the rest of the match with the first four games lasting 27 minutes, and despite being a break down, Del Potro recovered to seize what proved to be an important advantage.

Murray was second best to his big-hitting opponent but in the 12th game of the next set, the world number two broke Del Potro's serve to level the match and the momentum was with him heading into the third.

Both men had been on the end of questionable decisions from the umpire and line judges, but it did not prevent the pair from putting on one of the most absorbing sets of the year, with Murray saving a set point with a top-spin lob before taking a tie-break 7-5.

There was every expectation that Murray would outlast Del Potro but like in their Olympic final last month, all of Del Potro's best attributes were on show in Scotland and his heavy-hitting began to take its toll on the home favourite.

After needing just 34 minutes to take the match into a deciding set, Del Potro struck midway through the fifth before serving out for one of his most important victories of an injury-hit career.

Leon Smith will now be relying on Kyle Edmund in the second rubber, with the 21-year-old facing Guido Pella - a player who beat him in their opening previous meeting at this year's Indian Wells Masters.