After dropping a 116-111 decision to the Pistons on Friday, Houston (9-9) lost 117-108 in Cleveland on Saturday, the second stop on their three-game road trip.
Cleveland (4-14) hit five 3-pointers in the second quarter. The Cavs led by as many as nine in the first half and five at intermission.
"It's been a problem that we've had in the first half," Rockets coach Mike D'Antoni said. "We just give teams...we get them comfortable and then they feel good about themselves. And we pick it up in the second half, but a lot of times that's too late.
"But it's the first half that doomed us and we've just got to find ourselves again and right the ship again."
Another area the Rockets need help with is bench scoring. Rockets reserves are contributing 29.5 points per game, 25th in the NBA, and their shooting percentage (.427) is 27th.
"Our bench has to produce a little bit more," D'Antoni told the Houston Chronicle after Friday's loss. "We're not getting a lot of production there. It puts a lot of extra strain on the guys doing it, playing a lot of minutes with our starters."
Harden played the whole second half against the Cavaliers. He hit 14 of 30 shots and added 13 assists and has scored at least 30 points in four straight games.
The Wizards got 39 points from their bench, including some crucial fourth quarter baskets, in Saturday's 124-114 win over the New Orleans Pelicans.
Washington (7-12) caught the visiting Pelicans playing without leading scorer Anthony Davis and pulled away in the fourth quarter.
Otto Porter Jr. scored a season-high 29 points and John Wall added 22 points and eight assists. Austin Rivers scored 18 points off the bench and Bradley Beal had 18 points and eight assists for the Wizards, who had lost two straight games.
Porter made 11 of 14 field goal attempts, including 3 of 4 from 3-point range. The Wizards shot a season-high 56.7 percent (51 of 90) and outscored the Pelicans 56-46 in the second half.
"We just did what we needed to do, and it was all on the defensive end --that's where it came from," Beal said. "Our shots were equal, and we put up a nice amount of points, but our defense is what won us the game."
Markieff Morris' 3-pointer gave the Wizards a 109-104 lead with 6:53 left and Porter's tip-in in pushed the lead to seven. After Wall made a steal and fed Porter for an alley-oop, Washington was up 113-104 at the 5:15 mark.
Morris had 15 points and nine rebounds off the bench.