Miami's James Johnson looks to get past Otto Porter Jr. during the second half of Saturday’s 129-102 Heat win. (Lynne Sladky/Associated Press)

The Washington Wizards dragged themselves through a night of uninspiring basketball Saturday, starting the game by allowing three consecutive scores inside the paint and proceeding like punch-drunk defenders from there, playing on with their guards down while accepting more punishment.

As first-half offensive sets produced only missed shots or costly turnovers, the free fall continued, reaching an ugly third-quarter deficit. It culminated with a 129-102 loss to the Miami Heat, a team the Wizards had beaten in overtime four days previously.

This matchup at American Airlines Arena marked the Wizards’ second game in a back-to-back set of road matchups. While fatigue likely played a factor — although Coach Scott Brooks described the effort as “unacceptable” — Washington also seemed to simply be overmatched against a problematic opponent.

Miami’s guards pushed and attacked. The bigs bullied their way to the rim. The crop of backups continued this momentum and provided the additional wrinkle of an outside shot. In all, the Heat (36-31) played like a team gearing up for a playoff run while the Wizards (38-29) looked nothing like the team that had entered the night just a half-game behind the Cleveland Cavaliers for the third spot in the Eastern Conference.

“It was terrible,” Wizards forward Otto Porter Jr. said about the poor defense. “I think they scored about 100 points in the paint.”

Not quite, but the Heat controlled the interior and scored 76 points in the paint, the most the Wizards have allowed this season.

“We didn’t give any resistance,” Brooks said. “There were just putting their heads down and attacking us, and we had no protection at the rim. They outplayed us. There is no way around it.”

Brooks also offered that he was “disappointed” in himself and used the same word to express his feelings with the “our guys.” This disappointment reflected within the starting lineup.

Bradley Beal played 27 minutes and produced a minus-26 rating, finishing with 14 points on 5-for-12 shooting. The front line of Marcin Gortat, Otto Porter Jr. and Markieff Morris secured a combined 12 rebounds, while Miami backup center Kelly Olynyk grabbed 11 on his own. And after a halftime of adjustments, the Wizards still came out with the same woeful disposition and gave up 43 points in the third quarter.

“We just weren’t physical with them,” Porter said.

For the second straight night, the Wizards’ starters rested in the fourth quarter. Unlike Friday in New Orleans, when the team breezed to a 116-97 win over the Pelicans (playing without injured all-star Anthony Davis), Washington’s starters sat and watched their backups absorb the blowout.

At one point in the fourth quarter, Miami led by 38 and ignited a flood of bad memories from some of the Wizards’ worst losses of the season — including Dec. 4 in Utah and Dec. 22 in Brooklyn.

Repeating the same mistakes from those early-season letdowns, Washington looked slow defensively. Although Miami center Hassan Whiteside missed the game with a hip injury, Bam Adebayo and Olynyk filled in and combined for 19 rebounds. Forwards James Johnson and Josh Richardson handled the scoring punch and teamed to make 14 of 15 shots and score 33 points.

Early in the opening quarter, the Wizards had played a step or two behind, and certain plays exemplified this meager effort. Gortat stopped to lace his shoes before running back on defense. Miami recognized this five-on-four opportunity and an even more generous gift: no rim protection. Heat guard Tyler Johnson found Richardson for the layup — the team’s 16th point in the paint, and the quarter was not even halfway done.

“They just brought it to us, plain and simple,” Beal said. “They put their head down and basically picked us off one by one. Who they wanted to go at, they went at us and got whatever they wanted.”

Miami didn’t stop attacking the paint, and Washington never quite got a handle on the game. When Beal lost his dribble ahead of the halftime buzzer, his turnover was the team’s fourth within the closing two minutes. Washington had pulled within 46-44, but the sloppy ending allowed Miami to walk off the court with a 12-point lead.

After halftime, the punishment continued and the Wizards concluded the season series in a tie with the Heat.

“There is no excuse being tired,” said guard Jodie Meeks, who scored a season-high 23 points in nearly 28 minutes. “We just played these guys. . . . We got to bring a better effort as a team and just try to find a way to play better.”

Not e: Wizards guard John Wall joined the team in Miami and participated in a rigorous on-court workout before the game.

During his physical trial that lasted longer than 30 minutes, Wall showed a range of activity. In one drill, Wall attempted floaters in the paint while elevating off one foot. Later, he sprinted from sideline to sideline and lofted jump shots. Wall ended the workout by attempting corner threes until his teammates ran on the court for pregame warmups 15 minutes before the playing of the national anthem.

Although Wednesday will mark the sixth week since Wall had left knee surgery, Brooks said he will not return by that date. The team set the original timeline of recovery for six to eight weeks.