Wimbledon 2013: Jerzy Janowicz stands in the way of Andy Murray

For all the grumbling about the lack of stardust in the latter stages of the men's and women's singles draws at this year's Wimbledon, sometimes it takes a successful underdog to demonstrate what the biggest tournaments really mean.

Repeated success at the highest level brings with it a sense of entitlement. So that had Roger Federer played Rafael Nadal in the quarter-finals on Court One on Wednesday both men would have expected to be there and neither man would have been surprised had they won through to the semi-finals.

Instead, we were treated to the sight of Poland's Jerzy Janowicz, having seen off his compatriot Lukasz Kubot in straight sets, falling to the floor in sections, like a mighty oak, before surrendering his body to teary convulsions.

No pre-planned celebration, no calls for his sponsored watch. Just raw, unfettered emotion.

In his immediate post-match interview, Janowicz, who plays Britain's Andy Murray on Friday for a place in the final, was unable to convey to the BBC's Rishi Persad what victory meant to him - precisely because it meant so much.

A little later, the 22-year-old was still a little shell-shocked but able to make some sense of what had just happened. "This is a really big thing for me," said the world number 22. "This is what I was waiting for, this is what I was dreaming about: I made the semi-final of a Grand Slam.

"Sometimes if you are dreaming about something really hard, it can actually happen. I had some troubles during my career. So it's not easy for me to control these emotions. Right now I'm the most happy person in the world."

In common with many talented teenagers in the lower reaches of the ATP Tour, Janowicz's journey to the big league was a tortuous one. At least he made it, because many don't. Those that lack the money, the support, the necessary boldness.

In 2007, Polish New Yorkers clubbed together to buy him new tennis shoes after seeing him finish runner-up in the boys' singles.

After beating Murray in Paris last November, Janowicz revealed that his parents, former professional volleyball players, had sold off their chain of sports shops and apartments in order to keep their boy afloat. As he spoke, he was still without a sponsor.

But Paris was where the boy from Lodz became a man. All 6 feet 8 inches of him. Apart from Murray, Janowicz bombed out Philipp Kohlschreiber, Marin Cilic, Janko Tipsarevic and Gilles Simon, all ranked in the world's top 20 at the time, before losing to Spain's David Ferrer in his maiden ATP Tour final.

"He likes to play in front of many people on big stadium courts," says his Finnish coach Kim Tiilikainen. "He doesn't look up to the big names. He actually gets pumped up playing the top 10, as he thinks he can beat anyone."

Janowicz's remarkable sequence of victories in Paris moved a Polish rapper to pen a track about him: 'Bajka o Jerzyku czyli Niezwykle Przygody Jerzego Janowicza w Paryzu', which I am reliably informed translates as 'Fairytale adventures of Jerzy Janowicz in Paris'.

In truth, Polish rappers are probably more common than male Polish tennis players. Janowicz is the first Polish man to reach the semi-finals of a Grand Slam tournament. Before Janowicz's quarter-final encounter against Kubot, neither man had played a fellow Pole.

There isn't a single grass court in Poland and there was apparently consternation in his home country when Janowicz, inspired by his childhood hero and seven-time Wimbledon champion Pete Sampras, plumped for tennis rather than volleyball, which is one of Poland's national sports.

But victory over Murray would further popularise a sport which gained a foothold in the national consciousness because of the feats of Agnieszka Radwanska, who was the runner-up in the women's singles at Wimbledon in 2012 and was beaten in the semi-final this year.

Indeed, most of Poland's newspapers were featuring Radwanska on Thursday morning instead of Janowicz's straight sets win over Kubot.

However one of them had a canny prediction Janowicz could go all the way at Wimbledon, after talking to his former coach, Paul Jaroch.

Murray will certainly have his hands full against the Pole, who pounded down 30 aces against Kubot and can deliver a ball at 140mph.

Meanwhile, the millions of Britons standing on Murray's shoulders will expect a victory. For Janowicz's millions, victory will be a bonus: lose and they can get back to volleyball. Or rapping.

"I'm sure he feels some kind of pressure," said Janowicz when asked if the magnitude of playing the home favourite on Centre Court might get to him. "Because Great Britain is waiting for the British champion at Wimbledon."

For any patriotic Briton, anyone beating Andy Murray at Wimbledon is a bad news story. But if anyone does, let it be Jerzy Janowicz, at least so we know that fairytales can still happen in the all too prosaic and predictable world of modern sport.