MIAMI (AP) — Sluggish at times offensively, the high-octane Phoenix Suns unveiled a new wrinkle.

AP Photo/J Pat Carter. Phoenix Suns' Steve Nash (13) drives the ball between Miami Heat's Udonis Haslem (40) and Dwyane Wade (3) during the fourth quarter in Miami, Tuesday. The Suns won 104-96.

Zone defense, of all things, kept the Suns unbeaten.

Steve Nash scored 25 of his 30 points in the second half, added eight assists and the Suns used a dominant fourth quarter to beat the Miami Heat 104-96 in a matchup of NBA unbeatens Tuesday night.

“We’ve been working on it a little bit, but we haven’t really used it much or had much success,” Nash said of the zone, which Phoenix displayed in the second half for the first time this season. “I was just glad, more than surprised. It really came up well for us tonight.”

Sure did: Miami shot 35 percent in the second half, 23 percent in the fourth quarter. Phoenix missed fewer shots (15) in the entire second half than the Heat did (18) in the final 111/2 minutes.

Amare Stoudemire finished with 16 points and 11 rebounds for Phoenix, which overcame its largest deficit of the season. Jason Richardson scored 10 of his 14 points in the final period for the Suns, who are 4-0 for the first time since the 2004-05 season.

“We don’t read anything into being 4-0. We really don’t,” Suns coach Alvin Gentry said.

Miami got 23 points from Dwyane Wade and 18 from Quentin Richardson. The Heat (3-1) were bidding for their first 4-0 start in five years, and only the second in the franchise’s 22-year history.

“The zone changed our rhythm,” Heat coach Erik Spoelstra said. “We didn’t have a lot of answers for that.”

Phoenix came in averaging an NBA-best 117.3 points per game, and struggled during many stretches of the first three quarters.

The fourth, all Suns.

Jared Dudley’s driving three-point play with 7:03 left put Phoenix up 87-84, and for good. Nash capped it with 2:13 left, dribbling away from a Miami double-team for a three-point play that made it 102-93.

Nash made 10 of his final 11 shots, the only miss in the final 27 minutes being a turnaround 17-footer with 3:24 left in the third.

“I didn’t really play great in the first half,” Nash said. “I didn’t get a lot of opportunities, made some turnovers, so I wanted to get aggressive, give my teammates a chance to get back in the game — and got on a roll a little bit.”

The 35-year-old Nash is averaging 21.5 points and 12.5 assists so far, getting 17 points in the third quarter alone.

“He came out in that third quarter and put on a clinic,” Suns forward Grant Hill said. “It was really fun to watch.”

Hill scored 10 points with 12 rebounds for the Suns. Jermaine O’Neal — playing with a broken nose — scored 14, Michael Beasley added 12 and Udonis Haslem finished with 10 points and 13 rebounds for the Heat.

After the game, playing zone drew a lot of talk in the Suns locker room — and a bit of ire in the Heat locker room.

“I thought the zone was for college, personally,” Quentin Richardson said. “I thought that was the difference between the NBA and college.”

Miami led 26-23 after the opening quarter, which represented a small victory: It was Phoenix’s lowest-scoring period of the season. The Suns had scored 24 on three occasions.

Points were even tougher for Phoenix to come by in the second.

The Suns managed only 21 in that quarter and trailed by more than 10 points for the first time in this young season. Wade’s fast break dunk with 2:54 left put Miami up 50-37 and capped a 17-1 Heat run.

The Heat had another big burst in the third, scoring 11 straight to go up 68-56. They were outscored 48-28 the rest of the way, and Wade tipped his cap to Nash.

“That’s greatness,” Wade said. “You expect nothing but that out of him.”