Phoenix ? Avery Johnson put the “D” in Dallas. Then the coach put the Mavericks in the NBA finals for the first time in the franchise’s 26-year history.

Dirk Nowitzki shook off an awful start and the Mavericks’ defense shut down Phoenix in a second-half comeback, beating the Suns, 102-93, on Saturday night to win the Western Conference finals, 4-2.

Johnson, the NBA coach of the year in his first full season, focused on adding toughness and defense to a team known as a high-scoring, finesse squad.

“That’s the kind of defense we play under Avery,” Nowitzki said, “and it won us the game in the second half.”

Mavericks owner Mark Cuban, with the conference trophy perched atop his head like a crown, suddenly found himself in a place he’d never been – finals-bound.

“For the first time in my life,” Cuban said, “I’m speechless.”

Nowitzki, coming off a career playoff high 50 points in Game 5, scored 16 of his 24 points in the second half and the Mavericks clinched a series on the road for the third time in three tries in these playoffs.

Dallas' Dirk Nowitzki, right, works against Phoenix's Shawn Marion. The Mavericks defeated the Suns, 102-93, Saturday night in Phoenix to win their series, four games to two.

“We’ve been a good road team all season long, we believed in each other,” Nowitzki said. “We went through some ups and downs this season, but the playoffs is all about showing heart and playing together.”

Dallas opens the NBA finals at home against the Miami Heat on Thursday night. It will be a showdown of finals’ first-timers, the first time that’s happened since Baltimore played Milwaukee in 1971.

“Going into this season, nobody had Miami and Dallas in the finals,” Johnson said. “If you did, you won a lot of money.”

The Suns, trying to survive a fifth elimination game in the playoffs, appeared well on their way to sending this series back to Dallas for a Game 7: They shot out to a 16-point first-

quarter lead and were up by as many as 18 in the second.

But the Phoenix offense withered in a flurry of foul trouble, and the Suns fell in the conference finals for the second year in a row.

“An 18-point lead isn’t all it’s cracked up to be in a pressure game like this, especially in the first half,” Steve Nash said.

Dallas outscored the Suns 63-42 in the second half.

“It took a lot of energy for us to come back,” Jason Terry said, “but it took a lot out of them to let us come back, and then we were just full steam ahead.”

Josh Howard added 20 points and 15 rebounds for the Mavericks and Terry added 17 points, all in the second half. Jerry Stackhouse scored 19 for Dallas.

Boris Diaw had 30 points and 11 rebounds for Phoenix. Nash added 19 points and nine assists and Shawn Marion 13 points and 11 rebounds. Leandro Barbosa scored 14.

Dallas used a 17-2 outburst to claim its first lead since 2-0, 68-66 on DaSagana Diop’s rebound stuff shot with 9:42 remaining. Stackhouse’s three-pointer with 5:01 left put Dallas up 83-77. Howard’s three at 1:29 clinched it at 93-83.

“This was a special night for us,” Johnson said. “We were so bad in the first half and so good in the second half. The way we turned it on from the middle of the third quarter on into the fourth was incredible.”

An emotional Suns coach Mike D’Antoni praised the character of his undersized unit, which was shorthanded even before Raja Bell slightly tore a calf muscle in Game 1, then missed the next two games. He played the final three, but was never his old self.

“Raja is probably the most courageous guy I’ve ever seen, and he was playing on half a leg,” D’Antoni said.

Nash thought the team may have simply worn down, unable to keep up the energy that was so necessary for its success without big Amare Stoudemire, who missed all but three games this season because of knee surgery.

The Suns needed seven games to beat the Los Angeles Lakers and Clippers in the first two rounds, and led at the half in five of the six games against Dallas.

“I don’t know if you can pin it all on fatigue,” Nash said, “but I also think it would be ignorant not to say it played a part.”