Sam Querrey could be the first American man to win a Grand Slam since 2003. (Photo: Getty Images)
Before last year Sam Querrey had been a professional tennis player for a decade without ever breaking through to a Grand Slam quarterfinal.
 
Now Querrey, 29, is into his third career major quarterfinal at the US Open and is two wins from playing in Sunday's final.
 
"It's still kind of new," the 6-foot-6 San Francisco native said after his 6-2, 6-2, 6-1 fourth-round victory over Mischa Zverev on Sunday night. "It's still really exciting. It's a fun stage to be on. I think it's nice to have played a few [quarterfinals] already."
 
No American man has won a Grand Slam title since Andy Roddick captured the 2003 US Open -- 14 years ago. And No. 17 Querrey is the first American in the quarterfinals in New York since you guessed it, Roddick in 2011.
 
Meantime, five Europeans -- Roger Federer, Rafael Nadal, Novak Djokovic, Andy Murray and Stan Wawrinka -- have accounted for 51 of the last 55 Grand Slam titles.
 
Querrey remains in contention to snap the American drought, but he's not thinking that far ahead.
 
Next up on Tuesday is a big server who is similar to Querrey, 6-foot-8 South African Kevin Anderson, the No. 28 seed. Querrey is 8-6 all-time against him.
 
"He's another one that is tough to play," Querrey said. "He doesn't give you much rhythm. He can go games where he's serving huge, you don't get a ball in play. He takes big cuts from start to finish. If he's on and he is dialed in, he's one of the toughest guys to play out there. You have to weather the storm against him, know he's going to have some brilliant shots."
 
"But I feel like when my game's on, I have a dangerous game as well. Hopefully, it will be a match where each guy might have a small opportunity here and there, but we'll see."
 
Before this year, Querrey may have been best known for stunning world No. 1 Novak Djokovic in the third round at Wimbledon in 2016. At the time, Querrey was a 30-1 underdog and Djokovic held all four Grand Slam titles. Querrey went on to lose to Canadian Milos Raonic in the quarterfinals.
 
This year at Wimbledon, Querrey shocked another No. 1 when he defeated Andy Murray in five sets in the quarterfinals before losing to Marin Cilic in the semis.
 
Now here he is with a golden opportunity at his home Slam to come through the bottom half of the draw, which as John McEnroe said, is wide open enough to "drive a Mack truck through."
 
Murray, the No. 2 seed on the bottom half, withdrew before the tournament with a hip injury. No. 4 seed Alexander Zverev, considered by many the favorite to come through the bottom half of the draw after Murray pulled out, lost in the second round.
 
Now four unlikely contenders remain on the bottom half: Querrey, Anderson, No. 12 Pablo Carreno Busta of Spain and No. 29. Diego Schwartzman of Argentina.
 
"Yeah, obviously it's been a very different tournament," Anderson said. "Our sport's been dominated by such a select group of people for so long, it feels a little bit different. I think most sports are like this, where you do have multiple people contending. You've had some of the greatest players of all time playing in our time here."
 
Two of those players -- Federer and Nadal -- remained on the top half of the draw entering Monday's action.
 
On the bottom half, it's wide open for Querrey to make some history for American tennis.
 
Follow @AdamZagoria on Twitter for updates during the US Open.