Wimbledon: Andy Murray at his best to book semi-final spot once again THIS was surely Andy Murray's most complete Wimbledon performance to date. Over four sets and nearly four hours of play, the Scot traded punches with David Ferrer of Spain, eventually winning a tense quarter-final 6-7, 7-6, 6-4, 7-6. Murray threw everything he had into the Centre Court battle - patience, perseverance, physical strength, mental toughness and tactical guile. He chucked in more than a handful of unforced errors, too, yet still emerged a worthy winner against the seventh seed, to reach the semi-final for the fourth consecutive year. Andy Roddick defeated him at that stage in 2009, Rafael Nadal in the following two years. Roddick is not the force he was, and lost in the third round this year to Ferrer. Nadal is long gone too, having been sensationally knocked out a round earlier by Lukas Rosol. Since the former champion's defeat a week ago there has been much talk of the draw opening up for Murray. The No 4 seed has said little on the issue himself other than to point out that the absence of Nadal, whom he was seeded to meet in the semis, would only become relevant if he reached that penultimate stage himself. Well, he's there now, and although he will show every respect for Frenchman Jo-Wilfried Tsonga, his opponent tomorrow, he must fancy his chances of reaching his first final now. Indeed, without wishing to tempt fate, it looks like the fifth seed will not prove as tough an opponent as Ferrer did. If Murray does prevail, and thus reach a final against either defending champion Novak Djokovic or six-time former winner Roger Federer, he will have to cut down on that error count, which, according to the official statistics reached a total of 39 yesterday. He will want to cut down on it against Tsonga in any case, but the Frenchman plays a looser game than Ferrer - more inspired at times, more easily distracted at others - and so does not punish opponents" mistakes quite as ruthlessly. And Ferrer was certainly in punishing form yesterday, above all in the first two sets. In the opener, the 30-year-old from Spain broke Murray's serve to take an early advantage, and although the British No 1 broke back, Ferrer was undaunted. In the tiebreak, two of those unforced errors from Murray gave his opponent the edge, with the second conceding a set point. Ferrer converted it to win 7-5, and was a set up after a gruelling 67 minutes. Murray had been too tentative, an old failing of his, during an hour and a bit. He had failed to attack Ferrer's second serve, and had been decidedly below par on his own first serve, which he only got into play 51 per cent of the time. That was a marked decline on his exceptional performance in his straight-sets win against Marin Cilic in the previous round, and it was clearly something he would have to rectify if he was to get back on terms. The triumphant conclusion to the match, nearly three hours of playing time later, would demonstrate how successfully he did exactly that, As he has grown in experience, Murray, who turned 25 earlier this year, has become almost immune to the self-doubt which inflicts most players when they go a set down. He knows that nearly all of the time, even when an opponent is playing out of his skin, provided he hangs in there long enough, his chance will come. He proved that once more against Marcos Baghdatis in last Saturday's third round. The Cypriot was playing out of his skin, and at one point thumped his chest as if to assert that, contrary to what his doubters say, he had the heart to win. But Murray knew that as long as he kept going, doubt would set into Baghdatis's mind. And so it proved, as he won in four sets. The trouble with Ferrer, however, is that he is not quite so fragile a talent as Baghdatis. You can pose him any number of problems on court, and he will keep coming up with answers.That was the way most of the second set went. Ferrer had to save a break point in the second game, as Murray upped the tempo in a bid to hit back immediately, but it was the Scot who was in trouble in the seventh, when he needed to save three break points. Murray managed that, but was then broken in the ninth game to go 4-5 down. Ferrer only had to serve out to take a two-set lead, but this time when Murray upped the pressure the cracks began to appear. The Scot broke back, and two holds later it was time for another tiebreak, which this time he won, 8-6. Murray's serve was holding up better by this time, and as the third set went on his returningsteadily improved as well. That was nowhere more important than in the ninth game, in which he broke Ferrer to go 5-4 ahead. A minute or so later he was a set to the good, after an imperious service game which lasted just six points: a serve and volley, two winning serves and then an ace. Rain was in the offing as the fourth set progressed in almost orthodox fashion until an eighth game which, in retrospect, could be viewed as a microcosm of the whole match. Murray began slowly, committing a couple of errors to go two break points down, but he then fought back to hold. That made it 4-4, then two games later the rain did fall,forcing a suspension of around 20 minutes. Two more holds meant a third tiebreak in four sets, and although this time, too, Murray got into trouble, he served magnifiicently to clinch the match. Two consecutive aces got him back in front from 3-2 down, then a third at 6-4 up, on his first match point, brought an engrossing and exhausting contest to an end.