Having beaten Roger Federer's Switzerland and France on the road, the U.S. Davis Cup team now awaits a more daunting obstacle - defending champion Spain in the semifinals.
John Isner sent the Americans into the next round by winning Sunday's opening singles match - a 6-3, 7-6 (4) 5-7, 6-3 victory over sixth-ranked Jo-Wilfried Tsonga of France. The U.S. is in the last four of the Davis Cup for the first time since 2008.
"We've had the worst draw you could possibly imagine. I'm shocked that we're still in the Davis Cup this year," U.S. captain Jim Courier said. "We're going to be the underdog in Spain, but we're going to come with guns blazing."
Isner won both his singles in style, dispatching Gilles Simon on Friday and refusing to get rattled against Tsonga. Simon beat 19-year-old Ryan Harrison 6-2, 6-3 in Sunday's last match to make the final score 3-2.
In other quarterfinals, host Czech Republic topped Serbia 4-1 and host Argentina beat Croatia 4-1. The semifinals are in September.
Just like four years ago, the Americans beat the French to set up a series against Spain. That time, Spain won 4-1 at home on clay. Whether Rafael Nadal plays for Spain, Courier expects an intense series.
"Anytime you step on the court against Spain they're tough. They beat us at home last year without Rafa, on hard court, indoors," he said. "They have been the best team in the world for the past decade."
But Courier did not expect to beat Switzerland, either. And the Americans romped 5-0.
"At the beginning of the year it was my hope that we could stay in the world group because Switzerland away, you think you'll probably lose that match," he said. "Spain, we'll probably lose it on paper ... but we don't play them on paper. We've got players who are capable, passionate and hungry."
Isner certainly is.
"People didn't think we could beat Switzerland. I'm sure there were some people who didn't think we could beat France," Isner said. "The reason I played so well this weekend was because (beating) Roger in the first round was huge for me because prior to that I hadn't really played that great in Davis Cup. Took a lot of pressure off me."
The 11th-ranked Isner was quick to praise Courier's influence.
"He's definitely helped me. He helped in that first tie against Switzerland," Isner said. "He never gets too excited. He doesn't get too mad at us. He's a very even keel."
Isner was just as cool under the blue skies and sunshine at Monte Carlo Country Club. As for Tsonga, he was frantically trying to find out a way to get into the match.
"John played very close to his maximum," Courier said. "The quality of his match was exceptional. John is continuing to improve. I think he played even better than the last time (against Switzerland)."
Isner rose to the challenge, with the Americans unable to turn to ninth-ranked Mardy Fish, who was sidelined with fatigue.
"He's got great composure," Courier said. "When things are clear in your mind you're able to execute better."
Tsonga had opportunities but broke serve only once.
"I gave everything I could in the battle," Tsonga said. "I didn't have much luck today and John took his chances. At 0-3 down in the fourth set, it became 'Mission Impossible."'
Isner built on the U.S. team's momentum after Saturday's doubles victory in straight sets. He did not face a break point.
"Isner was huge today," France captain Guy Forget said after his last Davis Cup match.
Isner broke for a 5-3 lead and, having taken Tsonga's serve, made a statement with his next service game: holding to love and clinching the set in 34 minutes with another ace that whistled past Tsonga.
Isner appeared more troubled by a wasp fluttering around his face midway through the second set, failing several times to flick and then swat it away with his racket.
The tiebreaker went with serve until Isner smacked a big forehand down the line that rocketed past Tsonga. He clinched the set with yet another ace, timed at nearly 141 mph.
But Tsonga had to wait until the 11th game to actually break. The Frenchman found his touch and hit a crosscourt forehand on the run to make it 15-40. The American forced deuce, but Tsonga's two-handed backhand pass gave him another chance to break. He took it, prompting a huge roar from the crowd.
Tsonga took the set, but Isner stayed calm and took the match.