DALLAS, April 14 (Ticker) -- Ray Allen scored 13 of his 35 points in the fourth quarter, but even his circus shot could not keep the Seattle SuperSonics from falling to the Dallas Mavericks 109-106.

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After Dallas' Steve Nash missed a pair of free throws with nine seconds left, Allen hit a shot from just inside halfcourt to get Seattle within 108-106 with 2.9 seconds remaining.

"It happened exactly the way we drew it up," Seattle coach Nate McMillan joked.

The Sonics fouled Nick Van Exel, who made 1-of-2 at the line, but they could not get off a tying shot at the buzzer.

Dirk Nowitzki scored 39 points and grabbed 10 rebounds for Dallas (59-22), which moved a game ahead of Sacramento in the Western Conference. Although Sacramento has clinched the second seed in the Western Conference playoffs, the Mavericks will host a potential second-round series if they finish with a better record than the Kings.

"We've got to make sure we have a better record than Sacramento," Nowitzki said. "We're going to approach Wednesday's game (at San Antonio) like that."

The Mavericks lost a chance to earn home-court advantage throughout the playoffs when the Spurs defeated Utah. Dallas had the best record in the NBA for most of the season but has lost six of its last 14 games to fall out of the top spot.

"It would have been easier to have the best record," Nowitzki said. "We would have played Phoenix (in the first round). That's way better than Portland or (the Los Angeles Lakers) or anyone else."

The SuperSonics made the Mavericks work for the win, leading by as many as 12 points in the third quarter. Dallas took control, but Seattle clawed its way back to 102-101 when Allen made a layup with 1:10 left to cap a 15-4 run.

Nash answered with a 3-pointer, but the Sonics made things interesting at the end.

"We just needed to show some fight," Nash said. "We were really lacking energy and passion for a lot of the game, but finally we got it to come out of us and we fought. I think that's why we won."

There were plenty of interesting moments in the third quarter as Mavericks coach Don Nelson was ejected for with 9:14 left. With 51 seconds to go, Seattle forward Rashard Lewis was tossed for picking up his second technical foul and threw his mouthpiece at the officials as he left the court.

"(Dallas center Shawn Bradley) elbowed me right in the head," Lewis said. "I mean, I was laying on the floor. The second time, he stuck an elbow in my throat. I didn't even move and he just called it a foul on me. So I went to the ref and I said, 'He stuck his elbow in my throat.' So he gave me the tech.

"The next play down, he called a foul that wasn't a foul when I was holding Dirk. I turned around and started clapping and he threw me out. How can you throw someone out of the game for clapping their hands?"

Lewis had 21 points on 6-of-10 shootings. Reggie Evans added a season-high 13 points to go with 11 rebounds.

Dallas swingman Michael Finley returned after missing 13 games with a strained hamstring. He scored two points in 12 minutes and sat out down the stretch.