MIAMI - Remember how the 76ers were a national joke after losing to the Dallas Mavericks by 53 points on November 13? Well, no one is laughing now.

Especially not the Orlando Magic or the Miami Heat, the squads the Sixers (4-23) recently defeated to post their first back-to-back wins of the season.

They held the Magic to 88 points on Sunday at the Amway Center before limiting the Heat to 87 points Tuesday. The Sixers squad that once looked allergic to defense has been locking down foes.

"We've come so far," coach Brett Brown said Tuesday after his team's 91-87 victory over the Heat at AmericanAirlines Arena. "For all the work that we put in, it's actually coming to fruition. We are actually seeing some results."

The Sixers are the NBA's fifth-best team in regards to defensive efficiency in December. For the season, they've climbed 19 spots from 30th to 11th in that category.

"It validates my opinion that you can actually get better on things; we spent time on it," Brown said. "How much is always the argument. But we paid attention and we've been rewarded."

The Sixers trailed Miami by 23 points (69-46) with 8 minutes, 12 seconds remaining in the third quarter. They went on to outscore the Heat, 45-18, the rest of the game. Miami was held to nine points in the fourth quarter.

"We were just trying to keep the ball in front and not give them dribble-drives and make them hit contested shots," Michael Carter-Williams said. "We [were] able to turn them over [22 total] and capitalize off those turnovers, which was really big."

The Sixers scored 21 points off of Miami turnovers. They also blocked a season-high 11 shots. Ten of those blocks came in the first half. That was the most in a half by a Sixers squad since the 2005-06 squad blocked 10 shots in a half against Denver Nuggets on Dec. 27, 2005.

The Heat were held to 21 percent shooting in the fourth quarter, including 0 for 9 on three-pointers. Miami also missed its final seven attempts of the game.

"Going into this [five-game] West Coast trip [for] 10 days, I think we've got good momentum," Nerlens Noel said. "We've got Portland [Trail Blazers on Friday] and Golden State [Warriors on Dec. 30]. So I think we're coming in confident."