Considering the way Kaman's left ankle looked, those 20 points were just as impressive to coach Rick Carlisle.
Mayo tied a career high with 40 points, including 10 in the last three minutes, to lift the Mavericks to a 116-109 victory over the Rockets in coach Kevin McHale's return to the Houston bench.
Kaman left the Mavericks' last game on Thursday night with a sprained left ankle. He started Saturday night and played more than 18 minutes despite the left side of his ankle being almost completely covered by a deep purple bruise.
"Kaman showed a lot of guts even being out there," Carlisle said. "He went out there and gave us everything he had. He's obviously struggling laterally, but to put up the scoring numbers that he did is phenomenal. It's proves a lot to the team."
"With guys down ... and hurting a little bit, guys came and battled tonight," Kaman said. "O.J. played an unbelievable game for us. We got stops at the end on (James) Harden when we had to."
Harden had 30 points at halftime, but the Mavericks slowed him down in the second half. He scored just nine points in the second half.
McHale rejoined the team on Saturday after almost a month away from the team, and two weeks after the death of his daughter.
"It meant a lot to have him in the locker room ... and it showed how much he wanted to be here because he's been through a lot and he's here with us working," Houston's Carlos Delfino said.
McHale said he was excited to be back and hoped it was the right time to return. He said after the game that he has a lot of work to do.
"It was different being out there again," McHale said. "I had been away for a long time and we had put in some stuff. I've got to get caught up, so these next few days will be good for us."
A three-point play by Harden cut the Dallas lead to two points before a jump shot by Mayo made it 109-104. A 3-pointer by Toney Douglas seconds later put Houston back within two with about a minute to go, but Mayo's 3 seconds later extended the lead and the Mavericks held on for the win.
Carlisle also raved about Mayo, who tied a season high with eight rebounds, and has scored more than 30 points three times this season.
"What he is showing over the first 20 games is that he has the ability to carry a team at times, and it was really impressive tonight," he said.
The Rockets battled back from a 19-point deficit with a strong second quarter to lead at halftime and were up by nine points with 7½ to go. But Mayo got hot and the Rockets came up short as Dallas extended its winning streak in the series to eight games.
McHale took a leave of absence on Nov. 10 to be with his family as his daughter's health worsened. Alexandra "Sasha" McHale died Nov. 24 of complications from Lupus. She was 23.
Many of the Mavericks went over to McHale and hugged or patted him after introductions, and he received a standing ovation when the public address announcer welcomed him back to the team.
Dallas used a 13-2 run to take a 102-100 lead with about 4½ minutes left. Carter scored five points to power the run, and Brandan Wright capped it with a dunk.
Chandler Parsons made the second of two free throws for the Rockets before Mayo scored five quick points to extend the Mavericks' lead to 107-101 with less than three minutes left.
Parsons finished with 18 points and 10 rebounds, and Harden had nine assists and six rebounds.
The Rockets opened the second half with a 10-4 run to extend their lead to 76-67 with 8½ minutes left in the quarter. The Rockets continued their hot 3-point shooting from the first half early in the quarter as Harden and Jeremy Lin both hit 3s to power that run.
Dallas got going after that and an 8-2 spurt got the Mavericks within 78-75 with about five minutes left in the third quarter.
Houston was up by eight near the end of the third quarter, but Jae Crowder's 3-pointer with 15 seconds left cut the Rockets' lead to 89-84 entering the fourth quarter.
The Mavericks were up by 19 points with less than two minutes left in the first quarter after a long 3-pointer by Carter and thanks in large part to a 16-point quarter by Mayo.
Houston used a 35-15 run after that to erase the deficit and take a 55-54 lead four minutes before halftime. Harden scored 17 points and Houston hit five 3-pointers in that stretch. Harden had two of them, and he waved three fingers to the crowd while running down the court after the second one.
The Rockets shot 70 percent and scored a season-high 42 points in the second quarter to just 40.9 percent shooting by the Mavericks to lead 66-63 at halftime.
Houston's 42 second-quarter points marked the first time the Rockets have scored 40 points in a quarter since Dec. 31, 2010, against Toronto. ... Mayo has scored at least 20 points 11 times this season. ...