What they got was a bevy of players chipping in to pick up the slack.
"We've got so many weapons now," Harden said. "We've got a lot of depth on this team, a lot of guys that can contribute. When we've got so many guys contributing -- six guys in double figures -- it's kind of hard to beat us."
It was the third straight win for the Rockets and the fourth loss in a row for Dallas.
The Mavericks were down by 3 with 15.9 seconds left when Harden knocked Tyson Chandler down on a shot. He was given a flagrant foul after a review, but Chandler missed both free throws.
Terrence Jones blocked a shot by Monta Ellis but knocked it out of bounds, giving Dallas another chance. The inbounds pass by Chandler Parsons sailed out of bounds to give Houston the ball. Harden made two free throws after that to secure the win.
Ellis led the Mavericks with 33 points.
Dallas coach Rick Carlisle said his team was done in by its 23 turnovers.
"It was the decisive factor of the game, without question," he said. "We had chances, but that ultimately killed us."
Dallas scored five quick points to get within 3 with two minutes left, but Smith made a layup before blocking a shot by Chandler on the other end. Dirk Nowitzki made a layup before Harden's flagrant foul.
A 7-2 run by Houston pushed the lead to 95-87 with about three minutes left. That run was capped by a 3-pointer by Smith that came after an assist by Harden who was being heavily guarded by Rajon Rondo.
"I kick it out to him and he has the confidence to knock it down, and tonight he knocked a big one down in that fourth quarter," Harden said of Smith.
Smith signed with the Rockets last month following his release by the Pistons.
"I'm starting to find my way, starting to find spacing and other avenues to be productive and efficient," he said.
Brewer made the first five points of the fourth quarter to extend Houston's lead to 86-78.
Nowitzki made four quick points to cut Houston's lead to 2 points late in the third quarter before Jason Terry's 3-pointer made it 81-76. A jump shot by Ellis got Dallas within 81-78 entering the fourth quarter.
Ariza was scoreless before opening the second half with a 3-pointer and he made another one with about nine minutes left in the quarter. That shot was the first points of a stretch during which he outscored Dallas 10-7 to leave Houston up 72-66. A third 3-pointer by Ariza capped that run.
Parsons scored five points in an 8-2 run that tied it at 39 five minutes before halftime. Harden, who had eight assists, escaped pressure from Rondo with a nifty juke move and dished it Smith who made a 3 from the corner to leave Houston up 54-53 at halftime.
Mavericks: Parsons, who played his first three seasons in Houston before signing as a free agent with the Mavericks this offseason, got a smattering of boos every time he touched the ball in his second trip back. He had 21 points.
Rockets: Hall of Famer and former Rockets great Hakeem Olajuwon watched the game from a courtside seat. ... Smith made a season-high four 3-pointers.
HOWARD AILING: Howard has missed the last two games with a sprained right ankle, but after the game the Rockets announced that he's also dealing with swelling from fluid retention in his right knee. They said an MRI on Wednesday revealed the problem in his knee and that he'll undergo further evaluation soon.
WELCOME BACK: Jones (left leg nerve inflammation) played for the first time since Nov. 3 and received a standing ovation when he entered the game late in the first quarter. His first points came late in the first half when he swished a 3-pointer to give Houston a 44-41 lead. He was limited to just over 20 minutes as coach Kevin McHale tries to ease him back into the rotation after missing 41 games.
"I was just so anxious to get out there in the beginning, it got me a little winded early," Jones said. "But besides that, I had a lot of fun."
Mavericks: Visit Miami on Friday.
Rockets: Visit Boston on Friday.
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