With Kurt Thomas assigned to guard Tim Duncan one-on-one and Shawn Marion shutting down Tony Parker, the Suns squared the best-of-seven Western Conference semifinal series at a game apiece with a 101-81 victory.
Amare Stoudemire scored 21 of his 27 points in the second half to lead Phoenix.
Steve Nash, playing with a bandage over his nose after cutting it late in Game 1, added 20 points and 16 assists as the Suns beat the Spurs in a playoff game in Phoenix for the first time in five games dating to 2005.
Raja Bell added 18 points for the winners. Game 3 is Saturday in San Antonio.
The Suns' most significant contributions may have come from Marion and Thomas, who was added to the starting lineup.
"Defensively, we were really good," coach Mike D'Antoni said. "It started with Shawn and Kurt. Their work on those two guys was really good. Finally, we started clicking a little bit offensively. It was really a good effort. We just need to repeat it three more times."
Tim Duncan scored 29 points despite foul trouble for San Antonio. But the Suns didn't double-team him, and unlike Game 1, he got little help from his teammates.
"They decided to stay out of there and let Kurt deal with me," Duncan said. "So that's how it went."
D'Antoni's decision to start Thomas and have him defend Duncan freed up Stoudemire to concentrate on offense. As a result, Stoudemire had plenty of energy to counter Duncan's one-man show in the third quarter.
"I tried to hit a couple of jumpers to bring the big guys out of the paint," Stoudemire said, "but I said forget about it. I'm just going to take it to the rack, and that's what we did."
Thomas, meanwhile, added 12 points on 6-of-7 shooting in 28 minutes. The Suns are 8-0 with Thomas as a starter, but normally he has played a limited role off the bench.
"It's been tough on him not to play as much as he likes," Nash said. "At the same time, it's a tribute to what type of person, player and teammate he is that he can suffer a lack of playing time and then be able to step up in the biggest game of the season and play so well."
Thomas knows what he's expected to do whenever he is on the court.
"For me, I have to play defense," he said. "Especially coming into the league, playing for Pat Riley, playing for Jeff Van Gundy. If I wanted to get out there on the floor, I had to really stop some guys on the defensive end."
After scoring 32 in Sunday's 111-106 series-opening victory, Parker managed only 13 on 5-of-14 shooting.
Marion managed only five points, but his teammates and coach praised him as a key to the victory.
"Coach told me just go out there and play defense, don't even worry about scoring," Marion said, "so that's what I did."
The Suns took the lead for good midway through the second quarter and were up by 12 early in the third. The decisive blow was an 11-2 surge that began with a no-look, over-the-head pass from Boris Diaw to Stoudemire for a layup and ended with Thomas' inside basket on a feed from Nash that put Phoenix ahead 84-68 with 8:07 left.
Even though Duncan was back, the Spurs never threatened seriously again.
"The game was all about maintaining a pursuit and aggressiveness," Spurs coach Gregg Popovich said. "They did that in a variety of ways. It's disappointing. You have to have five guys committed to doing the same thing. It seemed like we had three, maybe four at times, but not five."
The evening didn't start out that well for the home team, though.
Phoenix shot 26 percent (6-for-23) in the opening quarter. Duncan, meanwhile, had 10 points and seven rebounds in the first, but just two points and two rebounds in his foul-plagued second.
The Spurs were misfiring, too, going 1-of-9 during an 11-2 Phoenix run to start the second quarter. Stoudemire's dunk, the Suns' first of the series, capped the spurt and put Phoenix ahead 30-27 with 7:12 left in the half.
Another Suns run, this one 9-2, boosted the lead to 41-35 with 3:06 to go in the half.
With a minute to play in the half, Duncan drew his third foul, on a charge against Nash, and Popovich got a technical in protest. Nash made the free throw to make it 46-39. The Spurs' Francisco Elson missed a dunk, leading to a three-point play for Bell to give Phoenix a 49-39 lead 25 seconds before halftime.
Bowen's 3-pointer cut it to 49-42 at the break.
Phoenix outscored San Antonio 7-2 to start the second half, taking a 56-44 lead on Stoudemire's dunk with 7:58 to play in the third.
The Spurs came back, cutting it to 65-60 on Bowen's third 3-pointer with 3:07 to play in the quarter.
The loss snapped San Antonio's five-game playoff winning streak. ... The Suns improved to 5-12 against the Spurs since Nash came to Phoenix in 2004. ... A local radio station passed out bandages for fans, including Suns owner Robert Sarver, to wear over their noses in support of Nash. ... D'Antoni turned 56 on Tuesday.