By Matthew Geagan, CBS Boston

BOSTON (CBS) — After two disheartening losses in Brooklyn, the Celtics are looking to turn things around with the series shifting to Boston. But if they want any shot against a Nets team led by three future Hall of Famers, they know it needs to start on the defensive end.

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Solid defensive play escaped the Celtics for much of the 2021 season, leading to disappointing night after disappointing night. Once a calling card of Brad Stevens’ team, defense became their biggest weakness as the season wore on. As defensive lapses piled up, so did the losses, and the Celtics finished the regular season with a defensive rating of 111.8.

Boston did play some pretty good defense against the Nets to start the series, holding the three-headed monster of Kevin Durant, James Harden and Kyrie Irving to just 33 first half points in Game 1. But then Brooklyn’s offense woke up, and Boston’s offense floundered in the second half. That led to defensive lapses by the Celtics, who were pressing too hard on offense, and the Nets won handily. Game 2 was …. Game 2 was just a bad night all around, and that all started with the Celtics losing Brooklyn’s sharpshooters along the perimeter throughout the first half. And when you let the Nets get wide open looks, they’re going to put the ball in the hoop.

So expect a much greater focus on defense when things tip off at TD Garden on Friday night.

“First game, I thought we were good defensively. Second game, we weren’t as good. We need to get back to being a little more solid and a little bit better on that end,” Celtics head coach Brad Stevens said after Thursday’s practice. “I thought we attacked a little bit better in Game 2. Hopefully, we’ll be able to build off of that heading into Game 3.”

Boston played better in the second half of Game 2, but at that point the outcome was decided. Given their first half bombardment against the Boston defense, the Nets were able to put it on cruise control before walking off their home floor with a 22-point win. And there isn’t much to take away from that 24 minutes of basketball, considering Jayson Tatum was off the floor for most of it after getting poked in the eye early in the third quarter.

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Tatum will be back for Game 3, and he’s confident the Celtics can slow the Nets down in Boston, no matter how well Brooklyn played in the first two games of the series.

“Regardless of the score of each game, it’s still worth one. Whether it’s a buzzer-beater or double digit win, they all count the same,” said Tatum. “Get that one behind us and prepare like we are now for Game 3.”

“We just have to play harder on the defensive end,” said Marcus Smart. “We lost one of the best shooters in this league multiple times. That’s just a lapse, a breakdown. Those are things we can control.”

Winning Friday night is also within their control, added Smart.

“We’re down 2-0 and we have a great opportunity to come out and make it a series by winning one,” he said. “We’re not trying to hit home runs. We’ve got to take care of what’s in front of us.”

“The edge, the pride, the competitiveness needs to be at its best level,” Stevens said of Friday night. “I feel good about things we’ve done in each of these games. Game 1 was more representative of how we have to play to be successful. We have to be much more physical. We have to be better defensively. Hopefully, we can attack better as these games go on.

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“Edge, competitive level is a huge huge part of the weekend,” added Stevens.