Johnson, who signed last week after being waived by Sacramento, joins a squad flush with talent. James Harden is a strong MVP candidate, Chris Paul has strengthened the backcourt and Clint Capela has developed into a low-post threat.
Johnson adds scoring punch off the bench, and he will seamlessly fit into the rotation, Houston coach Mike D'Antoni said.
"For us mortals, it would be real difficult, but for somebody like him, not much," D'Antoni told reporters Friday night. "I've known Joe forever and he's a machine. He just keeps playing, doesn't get tired, he's strong and just really understated in his game."
Johnson had 10 points in the Rockets' 120-102 victory over Minnesota on Friday. It was Houston's 11th straight win and 18th in the last 20 games.
On Sunday, they face a Denver Nuggets team that is also streaking, but not to the extent of the Rockets. Denver (33-26) has won 10 of 13 and is 7-1 in February. The one loss came Feb. 9 at Houston, but that was without forward Mason Plumlee.
Plumlee returned Friday after missing eight games with a right calf strain and provided a boost in Denver's 122-119 victory over San Antonio. His late dunk sealed the win, the Nuggets' fourth straight, and moved them within 1 1/2 games of the third seed in the Western Conference.
The biggest force behind Denver's strong month is center Nikola Jokic, who has notched three straight triple-doubles and six since Jan. 8. He is averaging 22.4 points, 11.6 rebounds and 9.8 assists in February.
"When you look at it, in the last 13 games, he is almost averaging a triple-double," Denver coach Michael Malone said after Friday's victory. "He's a hell of a player and I really want him to start getting the recognition he deserves. He is one of the best players in the NBA right now and he's proving it against good teams and the best players every single night."
Jokic has not put up big numbers in two blowout losses in Houston this season. He is averaging only 15.5 points and six rebounds against the Rockets. Houston won the first game in November by 30 and beat Denver by 26 earlier this month.
But the Nuggets feel like a different team than even two weeks ago. The Nuggets have beaten San Antonio twice and won easily in Milwaukee just before the All-Star break. The trick is to figure out a way to beat Houston, who has lost only four of 24 games since Dec. 29.
The Rockets are getting healthier, too. Trevor Ariza returned to the lineup Friday after missing nine games with a strained hamstring, and guard Eric Gordon could return after missing the win over the Timberwolves because of illness.
If Houston keeps winning, it will likely end up as the No. 1 seed in the Western Conference and set up a possible first-round playoff match against Denver. The Nuggets have shown they are not intimidated by good teams -- they've beaten Golden State, San Antonio and Oklahoma City -- but have hopes of finishing higher than the eighth seed.
"I really want this city to take hold of what we are doing and support them like they did (Friday) night," Malone said after the Spurs' win. "I think we have something special brewing here and it's a fun time to be a Nuggets fan."