Russell Westbrook "will be alright" after his injury scare for the Houston Rockets, while coach Mike D'Antoni was stunned by another sublime performance from James Harden.

Harden had 44 points, seven assists, five rebounds and five steals in 35 minutes as the Rockets finished their preseason campaign with a 144-133 road win over the Miami Heat.

Point guard Westbrook left Friday's game in the fourth quarter in visible pain and ran directly into the tunnel after hurting his hand, while Austin Rivers suffered with a shoulder problem.

D'Antoni explained Westbrook, who scored 16 points, had suffered a finger dislocation just two days after the same thing happened in Wednesday's game with the San Antonio Spurs, which had meant he played this one with a bandage.

The Rockets begin the NBA season at home against the Milwaukee Bucks on Thursday.

"With Russ it was just his fingers got dislocated," said D'Antoni. "Pop them back into place and then go play, he'll be alright.

"Both of them told me they were OK, so we'll take that. Austin said he was OK, I don't know exactly what that means but it is up in his [shoulder] – he also strained that in Washington last year."

The Rockets ended the preseason with a 4-2 record and hopes for a championship challenge are high after former Oklahoma City Thunder team-mates Harden and Westbrook were reunited in the offseason.

D'Antoni was lost for words by Harden's display against the Heat. He connected with 8-of-16 three-pointers and played like it was game seven of the NBA Finals.

"That's the way he's wired - he loves to play," added D'Antoni. "I couldn't take him out in the fourth quarter if I wanted to. He wanted to play and he'd play 48 minutes if he could.  

"James was ridiculous. He gets better every time. I don't know what his ceiling is but he seems to be the most improved player of the year for me, he's ridiculous."

Harden, meanwhile, was eager to get the regular season started after being asked for his initial feelings about how playing with Westbrook again had been.

"Great," the 2018 MVP said. "Now preseason is over with and we get to the real thing. It's gonna be a long season of just trying to communicate and be on the same page, not only me and Russ - our entire team. 

"This preseason was a good test for us, now we're excited for the real challenge."

Asked if this was the most powerful Rockets team since he had been with the franchise, Harden added: "Yeah, I think so."