DALLAS — The Dallas Mavericks already knew the Phoenix Suns were fast.

After watching Steve Nash, Shawn Marion and their running mates whiz past them in Game 1 of the Western Conference finals, the Mavs have a much better understanding of how quickly and relentlessly those guys race down the court.

"They got whatever they wanted," Mavericks star Dirk Nowitzki said yesterday. "They got like 100 points in transition."

Actually, it was only 32, but it was still the most Dallas has allowed all season. And it was a major reason why Phoenix pulled out a 121-118 victory Wednesday night.

Any hopes the Mavericks had about the Suns' legs feeling heavy after having gone the distance in each of the first two rounds faded quickly.

Running as often on shots that went in as those that didn't, Phoenix scored 14 of its 35 first-quarter points on fast breaks. By halftime, the Suns had 20 of their 62 points that way — and the Mavericks had a jarring reminder that they were no longer facing the San Antonio Spurs.

"You can talk about it all you want in a meeting or on the court, but it's difficult adjusting your game," Nowitzki said. "We've just got to get it in our heads that you can never relax no matter what happens. If it's a foul, a made basket, a miss — wherever you are on the court, you have to get back."

Dallas slowed Phoenix enough in the second half to take a nine-point lead with 3:43 left. Had the Mavs not committed four turnovers in the last 77 seconds or if Boris Diaw had missed a turnaround jumper with 0.5 seconds left, they would've withstood the Suns' open-court blitz.

But they still wouldn't have escaped the wrath of coach Avery Johnson.

Asked yesterday what his defense did wrong, Johnson said "transition defense" seven times in a row. He wasn't just being funny in front of the cameras, either, having blistered his players with the same message — in louder, more forceful terms — during a nearly hourlong film session.

"We had to close the doors," Adrian Griffin said.

The Suns know they can't expect the path to the basket to be as open tonight in Game 2. Johnson is certain to come up with something, like he did last round, when the Mavericks bounced back from a last-second loss in Game 1 to blow out the San Antonio Spurs by 22 points in Game 2.

Phoenix has its own recent Game 2 history to be wary about.

The Suns won the opener of both their series thus far, then lost the next game each time. They had a 14-point dropoff between Games 1 and 2 against the Lakers in the first round, then a whopping 33-point slide against the Clippers.

When Dallas and Phoenix met in the second round last year, the Suns won the opener then scored 21 fewer points in a Game 2 loss.

This time, Phoenix is facing the added challenge of trying to replace starting guard Raja Bell, who is out with a calf injury that could be serious. Leandro Barbosa will replace him.