BRITAIN’S Andy Murray hailed his tactics after beating US Open champion Juan Martin del Potro in the opening match of the ATP World Tour Finals.<br /><br />The world No4 came through 6-3, 3-6, 6-2 in front of 17,000 fans at London’s O2 Arena to make the ideal start in Group A of the eight-man tournament.<br /><br />The 22-year-old Scot used his defensive skills to counter Del Potro’s aggressive baseline play and afterwards he admitted he was relieved to get past his 6ft 6in opponent.<br /><br />“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,” he said.<br /><br />“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.”<br /><br />Murray went into the match with a 4-1 career record against the Argentine and he raced into a 5-0 lead before taking the first set.<br /><br />But Del Potro picked his level up in the second with some blistering forehands to take the match into a deciding set.<br /><br />However Murray saved his best serving for the third set and never looked in danger after breaking to go 3-0 up, and duly completed his victory in two hours and 10 minutes.<br /><br />Murray’s winning start was equalled by Roger Federer, but only after the world No1 battled back from a set down to beat Spain’s Fernando Verdasco 4-6, 7-5, 6-1 in the evening clash in Group A.<br /><br />Federer made the worst possible opening, being broken to love in the match’s very first game, and failed to recover in time to save the set. But the Swiss 15-time Grand Slam winner turned the contest around, finally breaking Verdasco in the last game of the second set to level.<br /><br />From there the momentum swung dramatically in Federer’s favour, and he saw off his opponent with the minimum of fuss.<br /><br />His victory put him joint top of the group with Murray and sets up a mouth-watering and potentially decisive clash with the home favourite tomorrow.