Britain’s Andy Murray gave home fans the perfect start to the ATP World Tour Finals with victory over US Open champion Juan Martin del Potro in the opening singles match at London’s O2 Arena.

The 22-year-old Scot won 6-3 3-6 6-2 in front of 17,000 spectators to take an early lead in Group A of the round-robin phase.

Making its debut in London, the season-ending tournament for the top eight players in the world got off to a strong start as the home favourite saw off one of the heaviest hitters in the game.

After the players had walked on to court to palpable excitement and the sound of London Calling by the Clash, there was an early fright for the crowd – and the organisers – when Del Potro called a medical timeout after just three games.

However, it was just to take care of a nosebleed and the 6ft 6ins man from Tandil recovered sufficiently from a slow start to ensure an absorbing encounter which saw his aggression from the baseline up against Murray’s defensive skills.

Murray went into the match with a 4-1 career record against Del Potro, but the 21-year-old Argentine has moved up the rankings to fifth in the world this season and – unlike Murray – has already won a Grand Slam title.

But since that dramatic five-set win over Roger Federer at Flushing Meadows, Del Potro has struggled with a wrist problem and won just two matches during the build-up to London.

There was no sign of that injury in the opening game as the huge, flat forehand that did for Federer in New York earned Del Potro an early break point, but Murray saved it with an ace and then took control.

The Briton was himself being aggressive on the forehand side and the extra variety in his game had Del Potro reeling, two drop shots leaving the US Open champion totally flat-footed as the first five games went to Murray.

It was enough to secure the first set but not before a comeback from Del Potro, who carried the momentum into the second and grabbed an early break as he began to find his range more regularly.

Murray appeared to have broken the Argentine’s resistance when he recovered the deficit in game five but Del Potro hit straight back to break again and sealed the set after 90 minutes with another blistering forehand winner.

A nervous finish appeared on the cards for Murray supporters but their man took the match away from Del Potro in the space of five minutes in the final set as he converted his second break point and then raced through a love service game for 3-0 before skipping confidently to his chair.

The Murray serve kicked into top gear in the closing stages and, with the watching Federer and Rafael Nadal getting a taste of the atmosphere inside the arena, the Scot broke again with a backhand winner to secure an impressive win in two hours 10 minutes.

“It was a really good start,” said Murray, who described the atmosphere as “excellent”.

“The start of the match was important. Me and Juan haven’t played that much since the US Open and I kind of expected a scrappy match. He didn’t start particularly well but I thought after 5-0 the standard was very good.

“He’s got a big serve, long reach, goes for huge shots. You just have to try and find a way through that. Tactically I’ve always been quite good so I found a way through it today.”

Del Potro confirmed that his medical timeout had been for a nosebleed, something he suffers from on a regular basis, but put the defeat down to Murray’s great start.

“Andy started to play very hard, very good,” said the Argentine. “He broke my serve very early and then he takes control of the first set.

“Against Andy the match is always very tough, we play three sets in every tournament, every match. Today was a little strange but he played great tennis in the third set. He was a little lucky but you need the luck to win, and today it was with him.”

Federer takes on Fernando Verdasco in the second Group A match later on Sunday, with Murray up against the winner in his next match on Tuesday – and he said he was already looking forward to it.

“I obviously need to try to win regardless of who it’s against,” he said.

“I think I’ll probably play the night match on Tuesday. It will be a great atmosphere again.”

Rafael Nadal, Robin Soderling, Novak Djokovic and Nikolay Davydenko kick off Group B on Monday.

The tournament began with a surprise in the doubles when defending champions and top seeds Daniel Nestor and Nenad Zimonjic lost to Polish eighth seeds Mariusz Fyrstenberg and Marcin Matkowski.