On Wednesday night, the Cavaliers, who improved to 7-23, outlasted the Wizards, 87-84.
Washington, which has lost eight straight, fell to a horrifying 3-23.
Cleveland has its first two-game winning streak of the season. Two of the Cavaliers' seven wins have come against the woeful Wizards.
"I should be a lot happier than I am, I guess," Cleveland coach Byron Scott said. "But some of the boneheaded mistakes that we made, some of the fouls, some of the things we did on the defensive end to allow them to have some of the shots that they had especially toward the end -- we've just got to be a little bit smarter when the game's on the line like that."
The Cavaliers' Kyrie Irving had 26 points -- 20 in the first half. He missed nine of his 10 field goals attempts in the second half, and 4-of-6 free throws in the fourth quarter.
"Oh, man, I started thinking too much," Irving said. "After I missed my first two, I moved back on the free throw line a little bit, tried some different things. It just wouldn't fall. It was frustrating. I'm glad it's behind me and we got this win."
Tristan Thompson's three-point play with 24.4 seconds remaining put Cleveland ahead. Irving made 1-of-2 free throws with 9.5 seconds left after Jordan Crawford and Garrett Temple missed jumpers for the Wizards. Crawford made two free throws with 8.5 seconds left to cut the lead to 86-84. Irving hit 1 of 2, and Crawford missed a 3-pointer as time ran out.
"We were able to sneak one out tonight," said Thompson, who had a season-high 15 points and 12 rebounds.
Washington took a 79-73 lead with 6:20 to play, but Cleveland scored nine straight points to take an 82-79 lead with 3:37 left.
The Wizards were held scoreless for 4½ minutes until Okafor hit a hook shot with 1:50 to play to cut the Cavaliers' lead to 82-81. Irving missed two free throws with 1:01 to play, and Okafor hit one of two with 46.2 seconds to play for an 82-all tie.
Washington had four turnovers in the last 5 minutes.
"We turned the ball over at crucial times. We won't commit -- all of us -- won't commit to playing defense. We make too many critical mistakes because we're just not alert down the stretch," coach Randy Wittman said.
"We've got too many guys that worry just about shooting the basketball and not about the other parts of the game."
Okafor had 10 rebounds to help Washington outrebound Cleveland 51-38.
"For the most part, we played them pretty well defensively, it's just the turnovers," Okafor said. "We had 20 turnovers to their 10, so in a three-point loss, there you go."
The Wizards broke on top 22-10 with 4:51 to play in the first quarter, thanks to Nene's 10 points. Cleveland's Irving had 12 of his 20 first-half points in the second quarter to help the Cavaliers grab a 45-43 halftime lead.
Washington started Shelvin Mack at the point. It was Mack's first NBA start. The second-year guard had been cut by the Wizards at the end of training camp, and re-signed on Tuesday after a strong stint in the D-League.
Mack was starting because Crawford was late to Wednesday's shootaround, according to a team source. Before the game, Wittman said that Crawford was benched for a violation of team rules. Crawford left the locker room before the media was allowed in.
Mack, who injured his groin and didn't play the last 4:11, had six points, seven assists and six rebounds.
The Cavaliers won their season opener with Washington, and nearly two months later, beat the Wizards again. They play again March 12 in Cleveland.
"The NBA hasn't done us any favors as far as the schedule, period. You've got two teams that are struggling a little bit, obviously. Us and them. Right now we feel pretty good about the two wins. Now it's just trying to build on them," Scott said.
Shaun Livingston, who was waived after Saturday's game by the Wizards, was on the Cavaliers' bench after his Tuesday signing. Scott said he would evaluate Livingston, who's playing with his seventh NBA team, after Thursday's practice. ... Cleveland C Anderson Varejao missed his fourth game with a bruised right knee. Scott said he would be evaluated on Thursday. ... Temple, who signed on Tuesday, had two points.