If the Mavericks had driven rental cars to the game Tuesday night, they should have been subcompacts to match their economy of gumption in the first three quarters.

But before they got into a complete rut with their smallish display of passion against Seattle, the Mavericks got a little energy upgrade from the guy who never seems to settle for cruise control.

Dirk Nowitzki hit a 3-pointer. Then he grabbed a couple of defensive rebounds and canned a 15-footer. And just like that, he put a nice, secure air bag around what had been a head-on collision waiting to happen.

The Mavericks pulled away after Nowitzki burned rubber for a few minutes, lapping the Sonics 99-83 at American Airlines Center. The victory wasn't pretty, but it pushed them closer to clinching a playoff berth. Two more wins in the final four games will do it.

And while style points were lacking against the Sonics, the bottom line was great.

"Ugly games also count as wins," Jason Kidd pointed out. "This is not a bad time to start playing your best basketball, no matter who you're playing against."

His point was that the Mavericks suffered a human-nature letdown against the lottery-bound SuperSonics. Yet they still played well enough when they had to, finishing with a routine blowout even though only five points separated the teams early in the fourth quarter.

They ended up shooting better than 50 percent. The Sonics were stuck at 38 percent from the field, and the Mavericks wore them down with 46 points in the paint to just 30 for the Sonics.

And while Nowitzki finished with just 11 points, seven of them (and five of his 12 rebounds) came in the first seven minutes of the fourth period, when the Mavericks salted away the game.

"I don't think it was pretty out there through three quarters," Nowitzki said. "Seattle kept battling, and we had some errors at both ends of the floor. But in that fourth quarter, we turned it up just in time and won the game."

Nowitzki continues to recover from a high left-ankle sprain and played just 26 minutes against the Sonics. He said he was stiff all game.

That gave him plenty in common with his teammates in the early going.

"It looked like he was a little tired early and sometimes when you come back from injury you may have three or four games and then one where you just feel like you're running in cement," said coach Avery Johnson. "It was a big, emotional game we had on Sunday [winning at Phoenix], and I could sense we were a little lethargic.

"Hopefully, because of that we had a little more left in the tank in the fourth quarter."

Jason Terry had 22 points on 9-of-11 shooting, and the Mavericks got 33 points from their reserves, 20 more than the Sonics got from their bench.

And, of course, the quick hit from Nowitzki in the fourth quarter made all the difference. Even if he's nowhere close to 100 percent, he made the difference.

"I wish I could do the things he does at 60 percent," Kidd said.