"Maybe in a weird way getting into it might have helped me," Roddick said. "That's the best I focused for a set this week. That's probably the best I played in a set this week. I knew I had to bear down."
Roddick yelled at himself after his numerous errors, kept up an argument with the chair umpire for many games, hit a ball into the upper deck to earn a code violation warning, and had a few run-ins with Spadea.
At one point, Roddick hit a short ball right at Spadea, almost hitting him. The two also jawed at each other during the break after the second set.
"We were probably annoying each other," Roddick said. "It's just part of it. It's not the first time something happened like that. It probably won't be the last."
Roddick admitted there's some resentment of Spadea because of a tell-all book he wrote last year titled, "Break Point: The Secret Diary Of A Pro Tennis Player." But Spadea doesn't think the book has led to bad blood with his competitors on tour.
"I don't think so," he said. "I don't think most players read the book. There's no way someone read that book cover to cover."
The momentum of the match changed after Spadea won the tiebreaker with three sharp volleys before Roddick missed wide on a backhand.
Roddick held serve to start the third set and then broke Spadea at love _ taking advantage of three errors on groundstrokes and a double fault on break point. Roddick broke again to go up 5-1 and closed it out on his serve.
"I just lost the momentum. My energy kind of went down," Spadea said. "I made too many unforced errors in that one game. ... I just didn't use the momentum in my favor."
Roddick, a two-time champion here, will play the winner of the match between defending champion Andy Murray and Lee Hyung-taik in the semifinals. Murray beat Roddick in the semis here a year ago, on the way to his only career ATP Tour title.
The other semifinal pits big-serving Ivo Karlovic against sixth-seeded Benjamin Becker. The unseeded Karlovic knocked off his second seeded American in as many days, recording 17 aces to beat fifth-seeded Mardy Fish 7-6 (2), 6-4.
Karlovic, who is ranked 103rd in the world, had 29 aces in his three-set win Thursday over second-seeded James Blake.
With his serve topping 140 mph at times and coming at odd angles from his 6-foot-10 frame, Karlovic never faced a break point on his serve and won 28 of his final 30 points on serve to put away Fish.
"It just doesn't really seem like tennis," Fish said. "It's not very often you play a match and you're excited when it gets to 40-30."
Karlovic got the only break of the match in the third game of the second set, taking advantage of a double fault and net-cord winner to earn two break points. Fish saved one with a service winner, but then missed wide with a forehand to lose the game. He slammed his racket to the court in frustration, figuring his chances of breaking Karlovic were slim.
Karlovic proved that to be true, holding his serve at love the next game when Fish couldn't get a single return in the court during the game.
Fish was dominant on his serve most of the first set, winning 18 of 19 points during a stretch leading up to the tiebreaker. But he hit a forehand long on his first service point of the tiebreaker to fall behind 2-0 and then hit a backhand into the net to give Karlovic a 5-2 lead. Karlovic served out the set with a 134 mph ace and a service winner.
"You get into a tiebreaker and every point is so big," Fish said. "You haven't hit very many balls the entire set, you get into it and he puts two balls in the court and you kind of panic because it's the longest point you'v had in 24 hours. You miss an easy shot and all of a sudden the set is basically over."
It's now up to Becker to solve Karlovic's serve, which has been broken just once in 39 service games this tournament. Becker got the only two breaks of his match against Marat Safin to advance to his second straight semifinal.
"It's going to be tough to return," Becker said. "If he's good on his serve, he knows he has nothing to lose on my service games because if he serves well he knows he can hold his serve easily."