DALLAS -- J.J. Barea and the Dallas Mavericks are hot at the right time.

The Houston Rockets, meanwhile are going in the wrong direction.

Barea added another clutch performance to the best stretch of his career Wednesday night, and the Mavericks buckled down for a crucial 88-86 win over the Rockets at American Airlines Center.

Dallas (40-38) won its fifth in a row and took a two-game lead over Southwest Division rival Houston (38-40) going into the last four games of the regular season. The Mavs and Rockets are locked in a three-team race with Utah (39-39) for the final two Western Conference playoff spots.

The victory also allowed Dallas to split the four-game season series with Houston. The Rockets would have taken the series and, more important, a playoff tiebreaker with a win.

Barea scored a game-high 27 points on 10-of-16 shooting, including 4-for-7 on 3-pointers, two days after being named Western Conference Player of the Week for the first time in his career. He added eight assists and five rebounds.

"It was vital," Dallas coach Rick Carlisle said of Barea's performance. "We had some other guys that had some struggling shot-making nights, and my message to the guys is we have to stay persistent and keep going hard."

As big as the diminutive Barea was on the offensive end, a defensive play by Dallas' longtime top gun helped the Mavericks hold on. Dirk Nowitzki, immersed in one of the worst shooting slumps of his career, stripped James Harden driving to the basket with Dallas holding a one-point lead in the final seconds.

The Rockets scored only 15 points in the fourth quarter.

"They got the physicality, they were very handsy, they did a very good job of keeping us out of a break, they jammed us in the backcourt, they smothered us in the backcourt," Houston coach J.B. Bickerstaff said. "We never got an opportunity to get the thrust that we needed, and from there it was a half-court game and the physicality took over a little bit from there."

Houston lost for the sixth time in nine games to fall into ninth in the West.

"I don't think there is anyone on this team that lacks confidence," Rockets forward Trevor Ariza said. "Look up and down the room. Everyone has different personalities, but lack of confidence, I don't think that's something that we do."

Harden scored 26 to lead the Rockets, but he shot only 8-for-22 and committed a game-high six turnovers. Rockets center Dwight Howard had 14 points and 16 rebounds. Reserve forward Michael Beasley added 15 points in 21 minutes.

Mavs shooting guard Wesley Matthews scored 16 and guard Devin Harris had 10 points off the bench. Nowitzki had seven points on 2-of-7 shooting and pulled down six rebounds.

Dallas has held each of its past five opponents to fewer than 90 points.

"The important thing is getting us into a position to win, and we have been able to do that," Carlisle said. "I am proud of our guys for being willing to be team guys and play this way."

Howard came to life in the third quarter by hitting the offensive boards and finishing strong. He gave Houston a 71-70 lead going into the fourth by tipping in an inbounds pass at the buzzer.

Barea scored 17 points in the first half, and the Mavericks took a 52-44 lead into the locker room. Matthews scored nine on three 3-pointers before the break.

The Rockets were down 12 late in the second quarter before two contested jumpers by Harden pulled the visitors within eight points at the break. Harden had 10 points in the half, and Beasley scored nine on 4-for-5 shooting.

The Rockets return home to complete a back-to-back Thursday night against the Phoenix Suns. Dallas has the Memphis Grizzlies coming to town Friday.

NOTES: It is unclear whether Dallas PG Deron Williams (sports hernia) will return this season. He missed his seventh consecutive game. ... Dallas PG J.J. Barea was named Western Conference Player of the Week for the first time in his 10-year career. "It was an amazing week for me on the family side, and then on the team side, we were able to win and I was able to help us as much as I could," said Barea, who also celebrated the birth of a daughter last week. ... Houston F Sam Dekker (back) said he was cleared to play, but it is unlikely he will see any action this late in the season. The rookie first-round pick has played in only three games since back surgery in November.