The Los Angeles Lakers' trade for Pau Gasol in the middle of last season helped the team evolve from a contender to the favorite in the Western Conference. The Houston Rockets are hoping their offseason acquisition of Ron Artest has a similar impact.

The Lakers look to remain undefeated as they host the transitioning Rockets on Sunday night in a matchup between championship hopefuls coming off uninspired victories.

On Feb. 1, Los Angeles acquired an All-Star forward in a lopsided trade by getting Gasol from Memphis in exchange for expiring contracts and some younger, unestablished players. The move instantly put the Lakers among the favorites in the West, and the team met those expectations by advancing to the NBA finals, where it lost to Boston.

Houston was another one of the conference's top teams last season, but it couldn't overcome the absence of Yao Ming in the playoffs, getting eliminated in the first round for the sixth straight time.

With Yao fully recovered from a stress fracture in his left foot and Artest on board following an offseason trade with Sacramento, the Rockets expect to end that drought this season.

To do so, however, they'll need to get past a shaky start. The Rockets opened 3-0, but dropped back-to-back games before grinding out a 92-83 victory over the winless Los Angeles Clippers on Friday night.

"Even though we won tonight, it still wasn't an impressive game for the Houston Rockets," said Artest, who had 23 points to lead Houston in scoring for the first time. "We're still searching to find ourselves.

"We haven't played good basketball yet. We need to play 48 minutes consistently. We have a long ways to go, but this was a good test for us. It's coming together and it's going to happen."

Yao is among the Houston players who are struggling, averaging 12.3 points and 7.3 rebounds over the last three games.

Though the Rockets escaped with a win Friday in their first of consecutive games at Staples Center, Artest knows they could use a more complete performance against the Lakers (4-0).

"We're trying to learn each other and find out how we're going to win together," he said. "Some nights it's just going to be different people, and we've got to get used to that. I think sometimes we just step into the arena and think we're going to win, just because of our talent. And it can happen like that. But that's not going to beat the good teams."

Though the Lakers certainly fall under that category, they didn't look like an elite club in their 106-88 win over the Clippers on Wednesday night. The Lakers trailed at halftime and shot below 40.0 percent for the second consecutive game, but they also held the Clippers to 38.9 percent shooting.

"When you don't shoot the ball well, you've got to defend," said reigning league MVP Kobe Bryant, who had 27 points and went 8-for-21 from the field. "That's what we did."

Coach Phil Jackson agreed with his star player, praising his team's ability to win when its shots weren't falling.

"The mantra is that defense wins ballgames, your offense comes and goes," said Jackson, whose team is looking for its first 5-0 start since 2003-04. "If you just rely on your offense all the time, it's going to disappoint you at some level."

The Lakers lost two of three against the Rockets last season, including their only meeting in Los Angeles in both teams' season opener. Houston's Tracy McGrady had 30 points in that game, but was held to a combined 20 points on 7-for-23 shooting in the other two meetings.

Bryant, meanwhile, averaged 33.0 points against the Rockets despite shooting 39.8 percent from the field in those three contests.

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