New York - He's a top 10 Swiss player, hits a mean one-handed backhand that has left John McEnroe purring and his name isn't Roger Federer.
For once, Stanislas Wawrinka, so often Federer's Davis Cup wingman, has outshone the 17-time Grand Slam title winner whose US Open ended in a fourth-round humbling.
Wawrinka, meanwhile, has reached the quarter-finals for a second time after his maiden run to the last eight in 2010.
Back then, he beat Andy Murray in the fourth round and on Thursday will meet the defending champion again for a place in the US Open semi-finals.
If 28-year-old Wawrinka ever suffered an inferiority complex in the Federer discussion, he shed it when he pushed world number one Novak Djokovic in a pulsating Australian Open fourth round match in January.
Djokovic prevailed in a five-hour duel, but Wawrinka had led 6-1, 5-2 at one stage.
"I think I am playing my best tennis ever," said Wawrinka, a close friend of Federer, with whom he won an Olympic gold medal in doubles in Beijing in 2008.
"I also think the title in Portugal (Oeiras claycourt event in April) against David Ferrer helped my confidence pass the next level. Since then, I'm feeling really good on the court," said Wawrinka, who made the last eight in New York by beating fifth-seeded Czech Tomas Berdych.
John McEnroe once described Wawrinka as having "the best one-handed backhand in the game today" and Wawrinka has been employing that weapon to increasingly effective use this year and in recent seasons.
In 2013, he won the title in Portugal, was runner-up to Rafael Nadal in Madrid, Ferrer in Buenos Aires and Nicolas Mahut at 's-Hertogenbosch.
He also enjoyed a quarter-final run at the French Open, where he was beaten in straight sets by Nadal.
His success this year reflects the slow-burning development of his career -- it took him five years to make his first quarter-final at a major, his run to the last eight in New York in 2010.
His passage to the quarter-finals this year is the first time that Wawrinka has gone deeper into a Grand Slam than Federer.
"It's a different situation, for sure. I'm really happy with the year and what I'm doing right now, but I would prefer to have him (Federer) still playing in the tournament," said the ninth seed.
"I was sad for him when he lost, because he's a good friend and I like when he's winning Grand Slam titles. I hope he will come back stronger."
Wawrinka, coached by former world number two Magnus Norman, could find himself battling with Federer to reach the World Tour Finals in London, the end of season showpiece which features the top eight men.
Federer is currently at seven in the standings while Wawrinka, who has never featured in the tournament, is on the outside looking in at nine.
Murray believes Wawrinka stands a great chance of breaking through but warns against writing off Federer.
"He's not that far behind Federer in the race this year, but there's still a lot of tennis to be played this year," said the world number three.