TENNIS:Who is Sloane Stephens? According to those swept up in the young American's three-set victory over a wounded Serena Williams to advance to the semi-finals of the Australian Open, she is the smiling, golden girl of tennis now, the future, a saviour for a game crying out for new blood – nowhere more loudly than in her own country.

It is a load and a half for a young player who has yet to win a single tournament in her senior career, who turns 20 in March and who suspects there will be many hard yards to play in the years to come, but has not been remotely exposed to the full rigours of her calling.

Even allowing for the vagaries of this perplexing game, however, her win was special, and so is she. She strikes the ball flat, hard and without fear. She has tennis smarts, picking the right moments, mostly, to gamble – as when, in the third set, she sensed Williams hanging back, hobbling with a bad back, so she undercut a delicious drop shot that spun almost sideways after skimming the net. She trusts that the net will not impede her most ambitious shots – soft or crunched with massive over-spin – and, if minor disaster looms, she believes it will be temporary. It is the upside of being a teenager in a world of gnarled elders.

In the immediate aftermath, she took a call from home. “I don’t know how I feel,” she said. “It’s still strange. I talked to my grandparents after. My grandma was just like, ‘Oh, good job’. They want to talk about my coach more than they want to talk about the actual match. I listened to them and they calmed me down a little bit.”

She will not be held back by false modesty, though. Asked if she had even dreamt of beating Williams, she said with calm beyond her years: “Last night I was thinking about it and I was like . . . someone asked me, like, ‘Do you think you can win?’ I was like, ‘Yeah, I think so’ – but I wasn’t like too clear about it. Then this morning when I got up, I was like, ‘Look, dude, like, you can do this’. Like, go out and play and do your best.”

She did, and how. There was not a trace of self-consciousness in her tennis. It was as if we were not even there with her. There was a court, a net and an opponent. She just let one shot follow another.

Beating Williams was, without doubt, a major shock – to Serena, to those watching, to the bookmakers who, at one point in running, had the kid at 1-750 – but not to Stephens. It was informative that she rated beating Laura Robson in straight sets in a way harder than beating Williams in three – because the latter was unexpected. There was no pressure.

Speed of foot

Stephens has good genes. She is the daughter of the late John Stephens, who was once a running back in the NFL. Not many on the circuit match her for speed of foot – or hand. She has steel-strong wrists that whip running forehands with lethal power, and send down serves of some heftiness. There will be days when none of this clicks, but they will probably be fewer than the good days, of which Wednesday was the best yet.

Her relationship with Williams is, on the available evidence, not cemented as full-blown friendship – and that is understandable from Serena’s point of view; she is not about to embrace a prodigy who, patently, is now a serious rival. Nevertheless, Williams betrayed a certain lack of grace in defeat, describing Stephens as “a good player”, and resisting the temptation to garland her day as it otherwise deserved.

They had contretemps of sorts in Brisbane, when Stephens complained to her coach that Serena’s “come ons” in mid-shot were “disrespectful”. Respect counts for a lot if none is freely granted, and Stephens has had to fight for any coming her way.

She was born in Plantation, Florida, to Stephens and Sybil Smith, a swimmer good enough to be recognised in an all-American selection, the first African-American to be so honoured. Stephens died in a car crash not long before the 2009 US Open, but Sloane decided to play.

She has been groomed as a potential shining light in the game for several years, having first held a racket, when she was nine. She came to notice first as a doubles player, but it was clear her all-round strength and speed were best suited to the lone skills of singles. In 2010, she reached the semi-finals of the junior tournament in Paris, then the quarter-finals at Wimbledon, but her concurrent achievements on the WTA tour were moderate, not surprisingly.

There followed the familiar round of wildcard entries and struggles through qualifying tournaments over the next couple of years, as she worked her way into the top 100. More people took notice at the French Open last year when she beat Ekaterina Makarova, Bethanie Mattek-Sands and Mathilde Johansson to reach the fourth round. She got to the third round at Wimbledon.

Rivalry

Her arrival was confirmed, fittingly, at her home tournament. She beat French Open champion Francesca Schiavone in the first round, Tatjana Malek in the second and came close to upsetting 12th seed Ana Ivanovic in the third. This was the tournament when Robson beat Kim Clijsters and Li Na. The rivalry was born.

When she beat Robson here, the London teenager was reluctant to acknowledge that she and Stephens were now set on a long road together, two bright and some times brilliant young players vying for the place in the sun soon to be vacated by the likes of Serena Williams. Robson, like Williams, did not want to hand Stephens an edge – and that is a measure of respect rather than jealousy.

When Stephens, who came here as the 29th seed, took that giving of respect out of Serena’s hands last night, it was hard won. She wanted no favours, and needed none. She had made her own way. Whoever Sloane Stephens turns out to be as a tennis player, she is already an engaging, fascinating young woman, an antidote to cynicism in a sporting universe drowning in the stuff.