DALLAS -- Tom Thibodeau, the notoriously gruff first-year New York Knicks head coach, cracked a hint of a grin when asked about his demeanor following a 117-109 win Friday night over the Dallas Mavericks.

It was New York's fifth consecutive victory, marking the franchise's longest winning streak in seven years. The Knicks, who had a losing record and failed to make the playoffs in the previous seven seasons, are sixth in the Eastern Conference standings with a 30-27 record.

"Am I happy? You know I'm never happy," Thibodeau said. "We try not to get wrapped up in all of that stuff. I think you don't want to get lost, and that's the most important thing to understand what goes into winning. I think if we're taking care of all the little things, the big things take care of themselves.

"I think we have a belief that we can win, and that's probably the most important thing. It started that way in the beginning. It doesn't really matter what outside people think. It's what we think."

The Knicks went 545 games between five-game winning streaks, the second-longest stretch in franchise history behind a 653-game stretch from 1958 to '66, according to ESPN Stats & Information research.

"We've just got to keep building," said All-Star forward Julius Randle, who has averaged 30.2 points, 9.2 rebounds and 6.4 assists during the winning streak.

Randle, a Dallas native who had several friends and family members in the American Airlines Center crowd, continued perhaps the best stretch of his career with a dominant performance against the Mavericks. He finished with 44 points on 16-of-29 shooting, 10 rebounds and seven assists, becoming the first Knick to have at least 40 points, 10 rebounds and five assists in a game since Bernard King in a March 22, 1985 win.

"He's making winning plays," Thibodeau said. "The way we started the game, his aggressiveness set the tone. I've said it many times: He's our engine. He makes us go."

Randle has been especially dominant in the past three games, scoring 34 points in Monday's win over the Los Angeles Lakers, 32 in Wednesday's win over the New Orleans Pelicans and a season-high-tying 44 on Friday.

Knicks guard RJ Barrett said he thinks it's no coincidence that Randle played so well against his two previous teams and his hometown Mavs, who didn't pursue Randle in free agency twice when they had ample salary-cap space.

"The way they made the schedule -- Lakers, New Orleans and then in Dallas and New Orleans again -- I mean, you kind of knew he was going to come out and do this," said Barrett, who had 24 points and eight rebounds against the Mavs. "It doesn't surprise me at all. He's a tremendous player."

Thibodeau cited Randle's improved 3-point shooting as a key in his success this season, as the Most Improved Player candidate is shooting a career-best 41% from 3-point range after going 6-of-11 in Friday's win. Thibodeau also raved about Randle's commitment to offseason conditioning to prepare himself to carry such a major offensive burden for the Knicks.

"It's a responsibility, but it's not something that weighs on me or anything," Randle said. "It's just my approach and who I am. I just try to be the same every day -- not try to be too high or too low. I am who I am. Come in and work, put my hard hat on, try to be unselfish and play for my team. Let that dictate the results."