The Nuggets go for their season-high fifth straight win and their 17th in 21 games with Billups in the lineup Tuesday night when they visit the inconsistent Rockets, who could be without Artest for the fourth time in five games.

Houston (15-9) traded for Artest in August, adding a third scorer behind Yao Ming and Tracy McGrady in an attempt to join the elite teams in the West. Partially due to injuries, the Rockets haven't yet made that leap.

They're 5-4 since Nov. 24 - the last time they played with Yao, McGrady and Artest. McGrady has returned from a seven-game absence because of pain in his surgically repaired left knee, but Artest has missed three of the team's last four games with a sore right ankle. He's day-to-day.

While the Rockets still feel like they have work to do, the Nuggets (17-7) have looked like top contenders since their acquisition of Billups in the first week of the season. After opening 1-3 without him, Denver is 16-4 since Billups debuted with the team.

The Nuggets have been particularly strong lately, averaging 109.9 points and shooting 49.9 percent from the field while winning nine of their last 11 games.

As impressive as Denver has been offensively, Billups' contributions on the defensive end have been the biggest upgrade. Billups helped Denver hold Dallas to a season-low 34.9 percent from the field in the Nuggets' 98-88 win Monday night.

"(Defense) was our main focus coming in," said Billups, a two-time member of the All-Defensive second team. "We knew coming in that this team is as good an offensive team as you'll find, so us being locked in and tuned into the game plan was important. We were able to contest all their shots."

The Nuggets will try to do the same against a Rockets team coming off a disappointing 95-82 road loss to the Los Angeles Clippers on Saturday night. Houston's point total tied its second-lowest of the season, and the team shot 35.6 percent from the field - also its second-lowest mark in 2008-09.

The Rockets were especially ineffective in the second half, when they were outscored 50-34.

"Missing the shots that we did really bogged us down," forward Shane Battier told the Rockets' official Web site. "We let it affect our movement. Games like this, when we don't move the ball and move ourselves, we normally lose."

The Rockets hope to rebound at home, where they've won four straight to improve to 7-3.

The Nuggets averaged 85.0 points and shot 38.6 percent from the field to lose both of last season's visits to Houston, where they're 3-10 since the beginning of the 2001-02 season.

Denver, though, delivered a convincing home win over the Rockets on Nov. 30. All-Star forward Carmelo Anthony played only 14 minutes in that game before leaving with an elbow injury, but Billups had a season-high 28 points and added 10 assists to lead the Nuggets to a 104-94 victory.