The Houston Rockets "can't play much worse" than they did in Game 6 against the Oklahoma City Thunder, said Mike D'Antoni.

The Thunder triumphed 104-100 on Monday to force a decisive Game 7 in the Western Conference first-round playoff series, with the Rockets paying the price for committing 22 turnovers.

With the scores locked at 98-98 heading into the final two minutes, Russell Westbrook twice gave possession away, airballed a jump shot and sent Danilo Gallinari to the line for the final points of the game.

Westbrook missed the start of the series with a thigh injury and he confirmed he will remain on a minutes restriction in Game 7.

D'Antoni said: "It's tough to come back right in the middle of a series when you've been out for three weeks, and also the whole lay off. He's fine, we'll be fine.

"We played about as bad as we could play. We will have to do a better job the day after tomorrow.

"We are going to respond. We'll clean up some things. We can't play much worse, so we'll play better.

"We just weren't sharp, got a bit careless a few times and we paid for it.

"We had 22 turnovers. You can't have 22. You try to get less than 10 and 22 just sealed our fate.

"Then we had some fouls that weren't disciplined. We had reach-in fouls that put them to the line and let them score, so things we can correct and will."

Asked why turnovers became an issue for the Rockets when it had not been earlier in the series, Westbrook said: "That's just my fault, honestly. That's easy. Last game I had zero, tonight I had seven. As simple as that.

"We've gotta take care of it, starting with myself. Just trying to figure out rhythm and timing, but we'll figure it out next game."

James Harden accounted for five of Houston's turnovers, which he felt undid the strong defensive performance they put in.

"A lot of careless turnovers. Including myself. Just too many turnovers, especially in a playoff game – a closeout game – just gave them too many opportunities," said Harden.

"I think defensively we did a pretty good job with them only scoring 104 points. We just shot ourselves in the foot by turning the ball over and giving us less opportunities to score."