PORTLAND, Ore., April 25 (Ticker) -- Dirk Nowitzki provided quite a finishing kick for the Dallas Mavericks.

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Nowitzki scored 16 of his 42 points in the fourth quarter as the Mavericks took a commanding 3-0 lead in their Western Conference first-round series with a 115-103 victory over the Portland Trail Blazers.

Dallas has won nine straight first-round games and sent Portland to its 10th consecutive postseason loss. The Mavericks can wrap up a third straight trip to the conference semifinals with a win on Sunday in Game Four.

"We were very focused and I am glad we got the third win, but because they moved it up to best-of-seven, it is not over," Nowitzki said. "We have to approach Game Four in the same way as we did the first three."

After trailing throughout, Portland got two free throws from Zach Randolph with 32 seconds left in the third quarter to take its first lead at 85-84. That only served as a wakeup call for Nowitzki, who fell just shy of his team playoff-record 46-point effort in Game One.

The German sensation, who also grabbed 10 rebounds, made his first five shots of the fourth quarter, including a 3-pointer for a 94-89 advantage with eight minutes remaining. He hit another shot from beyond the arc for a 99-93 lead with 6:32 to go.

"The one thing I told Dirk tonight was to get his teammates involved a little more," Dallas coach Don Nelson said. "Don't get me wrong, I still want him to be dominating, but he did a good job of creating shots for his teammates."

After a free throw by Portland's Ruben Patterson, Nowitzki again found himself open on the perimeter and drilled another 3-pointer as Rasheed Wallace flew by to give the Mavericks a 102-94 edge. It prompted a 20-second timeout by the Trail Blazers.

The break did nothing to slow Nowitzki, who dunked off a feed from Nick Van Exel and completed a three-point play for a 107-95 cushion with 5:10 to play.

"I am definitely sure we have broken their spirit a little bit, but they are still dangerous, they have a lot of pride and they are going to be hungry," Van Exel said. "We don't want to give that team a chance to think they have a chance to get into this series."

Ruben Patterson scored 18 of his playoff career-high 19 points in the first half for Portland, which has not won in the postseason since defeating the Los Angeles Lakers in Game Six of the 2000 conference finals.

The Trail Blazers are one loss shy of matching the NBA record for consecutive playoff defeats, set by the Baltimore Bullets from 1965-70 and matched by the Denver Nuggets from 1988-94.

Portland missed eight of its first nine shots in the fourth quarter.

"They are such a good offensive team, we just couldn't sustain us scoring the basketball," Trail Blazers coach Maurice Cheeks said. "At the end of the third quarter, we went up one to start the fourth and they continued to put the pressure on us."

Portland was without injured starters Derek Anderson and Scottie Pippen. Anderson injured his left knee in Game Two and Pippen has missed the last two contests with knee problems. It is unlikely either will make another appearance in this series.

Dallas placed six players in double figures as Raef LaFrentz scored 14 of his 20 points in the first half and Van Exel chipped in 14. LaFrentz made 4-of-7 shots from beyond the arc and Steve Nash had a double-double with 12 points and 10 assists.

"Raef played very well tonight," Nelson said. "I told Raef he had to score the ball."

Nowitzki made 15-of-20 shots, including 5-of-6 from beyond the arc, and scored 12 points in the second quarter. The Mavericks jumped out to a 16-4 lead and only the play of Patterson kept Portland close.

Nelson was whistled for a technical foul near the close of the half, and a tip-in by Randolph narrowed Portland's deficit to 64-61.

Bonzi Wells, who poured in 45 points in Game Two, missed all nine shots in the first half and fouled out with 15 points. Wallace was in constant foul trouble and finished with 11.

No team in the NBA has rallied from a 3-0 deficit and the Trail Blazers didn't sound confident about their chances.

"The way Dallas is shooting in this series, it's anybody's guess if we can beat them," guard Damon Stoudamire said. "When Raef LaFrentz can score 20 points, I mean he's a good player and all, but when he can add to the mix and hit those threes, it really stretches the defense."