Andy Murray of Great Britain celebrates his men's quarter-final victory over Spaniard Fernando Verdasco at Wimbledon.

Andy Murray of Great Britain celebrates his men's quarter-final victory over Spaniard Fernando Verdasco at Wimbledon. Photo: Getty Images

True to the theme of Wimbledon 2013, there was much falling down again on Wednesday, and two memorable feats of getting up again.

Andy Murray, whose Wimbledon cause has become his country's crusade, looked to have unravelled when he fell two sets behind Spaniard Fernando Verdasco, but picked himself up to win their quarter-final 4-6 3-6 6-1 6-4 7-5. Perhaps a metaphysical force was at work; bearing witness in the royal box was fellow Scot Sir Alex Ferguson, whose Manchester United so often nicked big games in extra time.

The magnitude of Murray's comeback might be judged from his bellow of self-recrimination at the end of the second set, inadvertantly shared with a national television audience: "What the f*** are you doing?"

In the first game of the preceding match, Argentina's Juan Martin Del Potro fell so heavily that he lay prone on the court for minutes, then had to be helped to his chair, crying, and it appeared that he would have to cede to Spain's David Ferrer.

Perhaps a compatriot also interceded for Del Potro, since his previous most cherished moment this year was to meet Pope Francis. At any rate, once set upright by pills and pride, he thumped Ferrer 6-2 6-4 7-6, whereupon he collapsed again, and the tears came anew, effects this time denoting joy. By this win, Del Potro doubtlessly won himself the highest honour in Argentine sport: he is fit to lace up Lionel Messi's boots.

In the other quarter-finals, no.1 Novak Djokovic beat Tomas Berdych in competitive, but straight sets 7-6 6-4 6-4, and in a meeting of Poles, not to be confused with north and south, Jerzy Janowicz overwhelmed Lukasz Kubot 7-5 6-4 6-4, so became the first man from his country to reach a major semi-final. All the day's winners and losers shared many hugs and conspicuously good grace; in this also, it seemed that a higher force was at work.

So, in a Wimbledon of unforseen heroes, two more emerged. Del Potro and Verdasco have in common that they are unfulfilled talents who have been invisible since 2009, when Del Potro won the US Open and Verdasco reached the semi-finals of the Australian Open, only to lose a five-hour epic to Rafael Nadal. Del Potro slipped only to the margins, Verdasco off the screen altogether, making Wednesday's siege of Murray all the more improbable.

Zoned off as Murray appears, maybe his country's dwelling got to him. He lost his first set of the tournament by double-faulting at break point. Then he lost his rhythm and range altogether, yielding his serve twice in a row and failing to exploit Verdasco when he fell 0-40 behind on his serve. A haunted version of Murray, timid and appprehensive, appeared in his chair.

But Verdasco has spent most of the year toiling in vain to win more than one match at a time, and Murray knew that as long as he could cling to him, he could drag him down. Consciously, he slowed his breathing and the pace of the match. To cover Verdasco's elaborate angles, Murray had to run not just the width of the court, but the stadium. He was up for it. In fact, he and Verdasco bidded each other up to a breathless level. Trailing in a service game in the fifth set, Verdasco hit a 180kmh second serve ace that landed on the T.

But Murray's nerve held. Evening's shadow had long fallen over the court when he at last consummated victory, though he waited several more minutes before daring to breathe again. In a dour summation that would have done Ferguson proud, Murray said: "I found a way to get through, and that's all you need." They also appear to share a general distrust of linesmen.

Del Potro's encounter with Ferrer was seconds old when he slipped and crashed so heavily that his racquet flew like debris. Already, his knee was sore from a similar fall four days previously. Now, as he lay prone, eyes full of tears, it seemed his Wimbledon was done. Del Potro admitted that he contemplated retirement. Time and painkillers wrought a miracle, and Del Potro retook the court, wincing and favouring his leg, but immediately staving off two break points.

Once injury was obviated as a factor, the difference was scale. Ferrer occupies the court, but Del Potro fills it, in every dimension. Ferrer hits the ball often and hard, but only as hard as he looks like he is hitting it, as hard as a man of his stature can, hard and often and well enough that on Monday, come what may, he will be world no.3.

Del Potro hits it so that it becomes like a slaughterman's bolt to the head of an export quality bull in his homeland, but more elegantly. His forehand to win, lasered seemingly through a ballboy's ears, was on his own cognisance his best shot of tournament. Ferrer turned himself inside out, and his shirt, once returning to the court with its seams on the outside, but to no avail. "Many bad things come to my mind, but I tried be positive," croaked Del Potro. "I never think of my knee after the first set, whether I was winning or losing."

Wimbledon's geography is such that Henman Hill, which was packed and ecstatic yesterday, faces over the top of court one to centre court, which means the other two quarter-finals literally were overlooked in the public imagination.

In the first, Djokovic did not fall as such, but did list a little. He trailed Berdych by a mini-break in the first set tie-breaker, then by two full-sized breaks in the second set, but recovered all these sundry deficits to win.

Berdych played into his hands with mistakes at crucial moments. When trying to stave off a third break of serve in the second set, for instance, he drove a ball into the net from pointblank range. Really, these so-called unforced errors were forced by Djokovic's sheer presence, and the certainty that he will punish the slightest faltering.

As he has purified his lifestyle in pursuit of success, so Djokovic is seeking — apart from a Wimbledon win — to cleanse his game of mistakes.

"I believe that you can always get better," he said. "It's something that keeps me going every single day. I know I have a quite complete game, but I still feel there are rooms for improvement. It excites me."

The clash of the Poles began with a hug and finished with another, this wrung through with emotion, and tears, and a soccer-style swap of identical white shirts. In truth, the symbolism of the match, certain to deliver Poland its first major semi-finalist, was more dramatic than its playing.

Janowicz, younger, higher ranked, taller by what seemed like metres, with a commensurately bigger game, always was in command. The foundation was his 30 aces. If listened to rather than watched, this match sounded like a distant mortar battle, with regular crumps, but almost no sound in between. Afterwards, the man with the overwhelming game was himself overwhelmed. "I didn't expect I can get this far, in Grand Slam, in Wimbledon," he said, his face streaked with tears, then, searching in vain for composure: "Really, I have not many words to say right now."

This, remember, was supposed to be Federer/Nadal. So might be traced the ruin, but also the making, of Wimbledon 2013. Or this way: the men's semi-finalists are ranked 1, 2, 8 and 22, and in the women's draw, 4, 15, 20 and 24.