Nadal faces scan on foot after battling victory

Rafael Nadal yesterday overcame both an ankle injury and a truly formidable opponent to extend his Wimbledon winning streak to 18 matches and reach the quarter-finals, where he will meet the tenth seed, American Mardy Fish. The defending champion beat the towering Argentinian Juan Martin Del Potro 7-6, 3-6, 7-6, 6-4 in an enthralling and incident-packed contest, the ominous skies overhead matched by the mood on Centre Court, especially when it seemed as if Nadal might be unable to continue.

After a lengthy medical time-out in the first set, however, the Majorcan seemed confident that he could rely on his heavily-strapped left foot – on which he will have an MRI scan today – and clinched the tiebreaker having trailed 0-3. But his opponent, angry both to have been made to wait for so long and to have conceded the tiebreaker with a double-fault, played thunderously in the second set, becoming the first man all tournament to take a set off Nadal.

He is also the first, and only, man to defeat both Nadal and Roger Federer in the same Grand Slam, which he did en route to winning the US Open in 2009. Del Potro has suffered grievous injury problems since then, requiring surgery on damaged right wrist tendons and missing almost the whole of last year, but nevertheless entered this contest with the swagger of a former Grand Slam champion. From the first exchanges there was plainly no sense of inferiority in the No 24 seed, who after all has climbed as high as world No 4, and in eight previous encounters with the world No 1 lagged only 3-5.

Del Potro is a devout Catholic, and also fervently believes that he is watched over on the tennis court by an older sister, killed in a road accident as a child. He carries with him an intense inner conviction that he is destined for the top. It was that conviction that helped him claim his US Open title, the championship he had always, growing up in Tandil, craved above all others.

Yet there was no doubting, in the south-west London gloaming last night, his burning desire to reach his first Grand Slam quarter-final since that victory at Flushing Meadows. Nadal was duly forced to scale the sublime heights of which he, and sometimes only he, is capable. But not until 2-2 in the fourth set did he break the mighty Del Potro serve. Both men played simply irresistible tennis, serving beautifully, belting winners down both flanks at the kind of speeds that the watching Red Bull driver Mark Webber might have recognised, and making gasp-inducing retrievals.

No less than Nadal, Del Potro was in the mood to take no prisoners. It has sometimes been suggested that the tallest man to win a Grand Slam is not best suited to grass, that at 6ft 6in he is just too tall to cope with the lower bounces that grass courts generate. But here he looked at least as comfortable on the green stuff as the bulls out on the Pampas. Boris Becker suggested the other day that there is simply no point trading baseline howitzers with Nadal, that the only way to beat him is to mix things up. That is what Del Potro did, wonderfully. But still the man on the other side of the net was, in the end, too good.

Showing how pumped up he was for the encounter, Nadal opened by serving faster than he had all tournament. And Del Potro was out of the blocks just as quickly, reaching 134mph in his own opening service game. "Vamos" was the repeated enjoinder on both sides, with the crowd making its own contribution to Spanish-speaking culture with a series of Mexican waves during the prolonged treatment to Nadal's foot. Later, Del Potro too needed medical attention, after slipping in the third set and damaging a hip.

Even without the medics it was a match full of incident, with Nadal furious to be given a time violation at 4-4 and 15-15. But it was his injury that at one point looked like dominating today's headlines. With uncle Toni, his coach, looking anxiously down, could it be that the defending champion, bidding to retain a Wimbledon title for the first time, and also to become only the second man after Bjorn Borg to win the Roland Garros-Wimbledon double on three occasions, might have to retire?

To the audible relief of the crowd, he soldiered on in pursuit of his 11th Grand Slam singles title, which would move him level with the great Rod Laver. Had Laver been present yesterday, he could have been forgiven for echoing what Bobby Jones once said about Jack Nicklaus: that Nadal, and Del Potro as well, play a game with which he is not familiar.