LeBron James goes over Emeka Okafor during first-half action. (Alan Diaz/ASSOCIATED PRESS)

When Jordan Crawford made a running jumper in the lane that brought the Washington Wizards within seven points of the Miami Heat with roughly seven minutes remaining in the fourth quarter on Sunday evening, center Emeka Okafor looked up at the scoreboard and thought to himself, “All right, here we come.”

Okafor had no idea where the Wizards were headed. Already the NBA’s lowest-scoring and worst-shooting team, the Wizards sank a little lower during a 99-71 loss at American Airlines Arena.

In a season in which games have too often been derailed by grisly offensive droughts, the Wizards found a way to go completely barren in falling to 1-15 on the road. The defending champion Heat finished the game on an incredible 21-0 run that Okafor couldn’t grasp until he walked through the tunnel and headed to the locker room.

“I didn’t even realize the run was that big,” Okafor said. “It kind of just happened like that. We were in the game and then we weren’t.”

The Wizards (4-28) failed to score at least 80 points for the seventh time this season — and for the second time in Miami, where the Heat has held them to an average of 71.5 points since a stunning defeat in Washington on Dec. 4.

“They a championship team,” Crawford said. “We played well enough to win. It’s just the difference between the two teams. They care about it more.”

Miami throttled the Wizards by 30 points on Dec. 15, when LeBron James personally outscored them 16-11 in the third period. On Sunday, reserve shooting guard Ray Allen personally outscored the Wizards 13-11 in the fourth quarter.

After Crawford’s jumper brought the Wizards within 78-71, Allen started the run with a three-pointer and scored nine points the rest of the way. He stole the ball from Martell Webster, streaked down the court for a layup and a three-point play, and closed out the scoring with another three-pointer.

“That’s a guy who mastered his craft,” Webster said. “He gets in here four hours before the game, just being here alone to get into that zone. Taking those shots. He’s knocking them down, but there is a reason why.”

There is also a reason why the Wizards continue to struggle offensively, with the team lacking many reliable scoring options. They shot just 35.6 percent on Sunday and had a roster full of players who struggled from the field.

Crawford, the Wizards’ leading scorer, had his least productive outing of the season, missing his first five attempts from the field and matching his season low with two points on 1-for-7 shooting.

Rookie Bradley Beal had scored in double figures in each of his past five games and was averaging 20 points in his previous three. With Dwyane Wade harassing him, Beal made just four field goals — including avoiding a James swipe before swooping down the lane for a dunk — and had more missed shots (10) than points (nine) as Wade, Allen and Chris Bosh all recorded blocks against him.

“It was kind of frustrating because they kind of knew what I was going to do and they blocked two of my pull-up jumpers and it’s something I’m going to have to adjust,” Beal said. “I just have to stay aggressive.”

Point guard Garrett Temple had seven assists but went scoreless and missed all seven of his field goal attempts, including an eight-foot jumper that concluded a fourth quarter in which the Wizards shot just 5 of 18.

“Got to contain teams like this from making big runs,” said Webster, the lone starter to score in double figures with 10 points. “Got to keep them from doing it. Can’t let it happen. It’s a game of will, but if you have one, there is a way.”

The Wizards thought they were deploying a secret weapon in Nene, who had led Washington to three consecutive wins over Miami with him in uniform (he missed the previous loss with a sore left foot) and had a personal four-game win streak over the Heat. But it didn’t take long for the Wizards to realize that one Nene wasn’t enough to counter James, let alone Bosh, Wade or Allen.

Bosh scored nine of his 17 points in the first five minutes, giving the Heat (23-9) an early 13-3 lead. It was the 14th time this season that the Wizards trailed by double digits in the first quarter. James finished with 24 points and Wade had 14 for the Heat.

The Wizards have lost five in a row and 13 of 14 overall. And they won’t have any chance to recuperate, because they will host the defending Western Conference champion Oklahoma City Thunder on Monday at Verizon Center.

That certainly isn’t enough time to solve a problem that has plagued them all season.

“You have to be able to score,” Coach Randy Wittman said. “We didn’t. So they went ahead and closed the game.”