Wimbledon 2013: 'Baby Federer', Grigor Dimitrov, stumbles in march of new generation

Sharapova's boyfriend lags behind Nishikori and Tomic in race to fill void left by top seeds

Grigor Dimitrov slips during his singles match with Grega Zemlja (Reuters)

With Rafael Nadal and Roger Federer gone, the young bloods are queuing up to make a name for themselves here. Today the man dubbed "baby Federer", Grigor Dimitrov, was fighting to stay in the tournament as the Australian Bernard Tomic and Japan's Kei Nishikori led the march of the next generation.

The 22-year-old wishes to be regarded as his own man rather than a clone of the Swiss and would also rather that attention was drawn to his tennis instead of his role in the so-called "love triangle" with Serena Williams and Maria Sharapova, who was watching throughout until the first rain of the week held up his close-fought match with Slovenia's Grega Zemlja at a critical stage.

Seeded 29, Dimitrov had failed to subdue an opponent outside the top 50, who led him 9-8 in the fifth set when to the crowd's frustration, the players exercised the option to come off. Since both men had required medical attention during the preceding three and a half hours of furious tennis, it was understandable.

Indeed, when the Bulgarian and Sharapova got together afterwards, the state of the courts may well have been a topic, Dimitrov having suffered a number of slips and slides against Zemlja similar to those his girlfriend endured in defeat on Wednesday. It will also have been at the back of his mind that, three years ago, his first seniors' match at Wimbledon was curtailed by a knee injury.

Sharapova may well have felt tempted to tell him that he should have killed the match instead of allowing a stubborn Zemlja to steal the second and fourth sets. If Dimitrov has a fault, it appears to be on the big points, which cost him and will do so even more against better players as he and the young generation push to take the next step up.

There is a belief that the average age of active players on the ATP tour may be creeping up. Britain's Kyle Edmund, given a wild card, was the only teenager in the main draw. Even 20- and 21- year-olds are thin on the ground. Tomic, born in October 1992, is as young as any of the survivors here; he made the third round by adding the scalp of James Blake, a veteran of more than 600 matches, to that of another American, the seeded Sam Querrey.

Winning in straight sets, Tomic showed no sign of the hamstring twinge that had caused him to retire from a doubles match against Dimitrov the previous evening; a problem he also suffered during the French Open.

He is growing up fast in having to do without his coach and father, John, who has been banned for allegedly assaulting his son's training partner. Tomic Jnr said he had raised the matter with the authorities without success, but now sounds much more relaxed about it, adding: "I don't think they'll be allowing him in, which is OK. I'm still seeing my dad. As soon as I get back to the house, he tells me what I've done and what I need to do. I think that's why I'm doing well, because I am listening to my dad a little more the past few weeks."

Tomic had a support team urging him on as he overcame the former world No 4 Blake 6-3, 6-4, 7-5. "It's not easy playing a guy like James and I felt really good," he said. The powerful Blake hit more aces and outright winners, but Tomic had the more reliable serve and all-round game.

The best of the new bunch, and one of the most watchable, could be the 23-year-old Japanese stylist Nishikori, already ranked 11th, of whom The Independent's Nick Bollettieri has said: "Shot makers like Kei come once in a generation." Today he found many, but not quite enough, of his best shots being returned by Argentina's Leo Mayer and was able to come through with increasing ease 7-6, 6-4, 6-2. Nishikori was once known, a little unflatteringly, as "Project 45" when the aim was to make him the highest-ranked Japanese player ever by beating Shuzo Matsuoka's 45th spot. He has comfortably done that and should go even higher than his current ranking.

Milos Raonic, who was born in Montenegro but moved to Canada aged three, has long been touted as the best of the new generation without achieving much at Grand Slam level, where he has yet to make a quarter-final. There will be none here for him either, for, unable to make the most of a serve reaching 139mph, he went down in straight sets to the Dutchman Igor Sijsling 7-5, 6-4, 7-6. The Canadian has been spoken about as a potential top-five player, but 22 aces were not matched by the rest of his game and a frustrating run of successive second round defeats was extended to a third Grand Slam.