DALLAS — The Rockets might break through, might finally get that elusive first road win, with some crazy hot shooting night. Such a thing is always possible, though Tuesday never threatened to be that.

They are more likely to find that win waiting on the other end of the floor.

Defense had forged their home-court success early in the season.

Defense had been their greatest strength, ranking first in the NBA as they headed out for a tough three-game road trip.

Defense let them down Tuesday.

Much of that was because of the brilliance of Luka Dončić, and the second-half surge provided by Kyrie Irving. But after the Rockets fell to 0-6 on the road this season, losing 121-115 to the Mavericks and getting eliminated from the in-season tournament, the Rockets knew it was their usual strength that betrayed them.

“Like I told the team,” Rockets coach Ime Udoka said, “Played well enough to win, not smart enough to win.”

The Mavericks matched the Warriors for the most points the Rockets had surrendered in four quarters this season, but that game at Golden State was in the second half of a back-to-back, rather than after three off days to get ready.

“We didn’t play our smartest game,” Udoka said. “We were extra aggressive, especially at the end of that third quarter. Had a six- to nine-point lead and could have extended it. Had multiple players make a few dumb fouls. Put Kyrie at the line to get him going when he didn’t have a lot going.

“So, didn’t love the end of that quarter. Once they get some free throws go down, they start to see the ball go through and they’re two of the better one-on-one guys. We had our chance.”

Udoka was especially annoyed by a Dillon Brooks foul of Derrick Jones Jr. on a deep 3-pointer that Jones rushed to launch with one second left on the shot clock. Jones’ three free throws gave Dallas a nine-point lead with 3:25 left.

“Socking somebody on the 3-point shot on the arm is an unintelligent play,” Udoka said. “It has nothing to do with aggression. Or picking up certain guys at halfcourt, it’s knowing who you are and who you’re guarding. You do that with an average player, but not with Irving or Dončić. We want guys to be aggressive, but we are fouling too much.”

Brooks agreed his foul of Jones was especially egregious.

“It was stupid of me,” Brooks said. “It was a bad foul on me.”

Brooks, however, added that if a game is called tight, Dončić ranks as the toughest of his nightly assignments against top scorers, saying in those circumstances he is “the best ever.”

“If they’re going to call those calls, he’s going to get whatever he wants,” Brooks said. “That’s a crew that calls a lot of stuff, anyway. I knew that going in and it doesn’t matter what I did.

“We play them a few more times. We’ll figure it out.”

Udoka had changed his coverages, starting the game with Alperen Şengün on forward Grant Williams, keeping him from dealing with the pick-and-roll lob threat of Dereck Lively II. That led the Rockets to switch extensively, and for Dončić to spend the night going one-on-one often even by his standards as the most frequent isolation player in the league.

“It’s pick your poison,” Udoka said. “He either goes one-on-one or tries to get everyone involved. He had a night. Somewhat kept the other starters contained. Lively had eight, (Josh) Green had five and Grant Williams had zero.

“We pride ourselves on individual defense and didn’t play our smartest.”

As often as the Rockets are in foul trouble, Udoka considered many of Tuesday’s fouls unnecessary and foolish. The Rockets commit more fouls than any team other than the 2-15 Pistons. Their 27 fouls Tuesday were one shy of their most this season.

Still, when the Rockets’ offense took off late in the first half and through the third quarter, they had surged to a nine-point lead with 1:25 left in the quarter. But they fouled Irving on each of the remaining three Dallas possessions in the quarter as he scored seven points in that sudden rush. Beginning with the Rockets’ largest lead, the Mavericks made 53.8% of their shots without committing a turnover the rest of the way.

“You got to find a way,” Rockets guard Fred VanVleet said of defending Dallas, and especially Dončić without fouling. “Dillon was battling, fighting all night. I thought we did a good job on (Dončić) at spots. But he’s one of the best in the league at drawing fouls. It puts you in the tight spot, gets you in the bonus.

“We’re right there. We’re playing hard enough. We’re competing at a high level. It takes a little more than that to take that next step, especially on the road.

Şengün gave the Rockets a late chance after the Mavericks surged to a nine-point lead, scoring 14 of his 31 points in the final nine minutes. VanVleet had 12 assists without a turnover and in the past four games has 41 assists with just two turnovers. The Rockets made half their shots. Every starter scored in double figures.

The Rockets just could not get stops, in part because of the Mavericks’ stars, but also because of their own missteps in the part of the game they consider their strength. Worse, they were the sort of mistakes that they have been unable to overcome on the road.

“They continue to happen game by game, it’s something you have to adjust,” Udoka said. “It’s not a coincidence. It’s not a ref calling something. If it’s similar action happening multiple games, you have to learn from that and adjust to it.

“We got guys bottled up and come over and hack them or foul them above the 3-point line when they’re in the bonus, or body up at halfcourt against one of the best drivers and give them a three-point play. It gets them going. We have to learn from that, show them, talk about it. But it’s not the first time happening. Have to adjust and be better.”