Moving from series to series in the playoffs doesn’t just require a change in game plan on defense, where you may have to modify your scheme to slow down your new opponent’s best players.

A series change can also require a team to adjust offensively to more effectively attack how the new opponent defends. The Boston Celtics did just that in their Game 1 of their Eastern Conference semifinals series against the Toronto Raptors.

The Celtics were the best pull-up shooting team in the regular season, with four of the 28 players who finished with an effective field goal percentage of 50% or better on at least 100 pull-up jumpers, according to Second Spectrum tracking.

Over their 72 regular season games, 56% of the Celtics’ jumpers (the league’s second-highest rate) were pull-ups rather than catch-and-shoot jumpers. That rate was higher (62%) as the Celtics swept the Sixers in the first round. Against a Philly defense designed to keep Joel Embiid near the rim, the Celtics ranked last in the first round in ball movement, averaging just 269 passes per 24 minutes of possession, according to Second Spectrum.

But the Raptors’ defense, which used ball pressure and relentless rotations to rank second in the league, requires a different approach.

“You got to make sure you get rid of the ball on time in this series,” Celtics coach Brad Stevens said before Game 1. “If you over-dribble, you’re in trouble. Isolation is not the answer. They just load up on you, so the ball has to pop, you have to move, you have to find a great shot when you can, and you have to be patient enough to find it.”

There was a clip from the 2014 Finals where Tony Parker told Spurs coach Greg Popovich, “I have to trust my teammates in this series.” Because the Heat were blitzing pick-and-rolls, Parker knew he would have to “get off the ball.” When he drew two defenders, he had to get rid of the ball quickly so his teammates could play 4-on-3 before the Miami defense recovered. He did just that, sparking the best ball movement we’ve seen in recent history.

The Raptors are not blitzing the Celtics’ pick-and-rolls. And Boston’s ball movement on Sunday was nothing like that of the 2014 Spurs. But it was clear from the start of Game 1 that the Celtics’ ball-handlers — Kemba Walker, in particular — knew they’d have to get off the ball against the swarming Toronto defense.

The Good Film: When the ball moves

Walker’s first touch of the series was on a hand-off from Daniel Theis, after which he was encircled by three Raptors: Fred VanVleet trailing the play, Marc Gasol (Theis’ defender) up high to prevent the pull-up 3, and Pascal Siakam pinching off Jaylen Brown on the right wing:

If Walker tries to drive, it’s not just Gasol he has to deal with.

“When you drive the ball,” Stevens said, “there’s going to be hands in the gaps, there’s going to be long arms in the gaps, swiping at every time you drive it.”

So Stevens wants Walker getting rid of the ball “on time.” The attention he’s getting from Gasol and Siakam has both Theis and Brown open for a quick pass.

Here’s that play and some other instances where Walker’s ability to pass quickly produced good looks for his teammates:

Play 1. Here’s the play above. Walker takes the hand-off and quickly gets the ball back to Theis with a pocket pass. OG Anunoby sinks off of Marcus Smart to help on Theis, who kicks the ball out to Smart for the first of the Celtics’ 10 corner 3s.

Play 2. Walker runs a pick-and-roll with Jayson Tatum (which the Raptors switch) on the right side of the floor. He quickly pitches the ball to Theis, who finds Tatum under the basket with a high-low pass over the 6-1 VanVleet. Tatum blows the layup, though.

Play 3. Another pick-and-roll (this time with Theis) from the right side has VanVleet pinching off of Brown, who creates a little more space by sliding over to the left wing. Walker quickly gets him the ball and Brown drains a 3 before VanVleet can recover.

Play 4. A high pick-and-roll has Ibaka up at the level of the screen. Robert Williams gets a clean roll to the rim (which Siakam fails to tag) and Walker hits him for a dunk

Play 5. With the Raptors in a 2-3 zone, the Celtics run their double-drag screen for Walker, who gets the ball to Brown as soon as he pops open. Brown is able to attack the seam of the zone and get the defenders moving. When Walker gets the ball back, he attacks another seam and hits the relocated Brown for another corner 3.

Play 6. A pick-and-pop produces a wide-open 3 for Tatum when Walker gets off the ball again.

The Celtics’ 300 passes in Game 1 were 59 more than they had in any of their four games against Philly. Pace had a little to do with that, but their 310 passes per 24 minutes of possession was also a much higher rate than they had in any first-round game.

After 56% of their regular-season jumpers and 62% of their first-round jumpers were pull-ups, the Celtics took more catch-and-shoot jumpers (27) than pull-up jumpers (26) on Sunday. They may have led the league in pull-up effective field goal percentage in the regular season, and shooting off the dribble is critical against most defenses in today’s NBA. But every team shot more effectively on catch-and-shoot jumpers than they did on pull-ups, and the Raptors’ defense is one that will give you some catch-and-shoot looks if you work for them.

The Bad Film: When the ball sticks

Habits can be hard to break and the Celtics didn’t always get rid of the ball on time. There were occasions on Sunday — a pull-up mid-range from Walker, a Tatum drive through traffic, a Tatum step-back off an iso — when they were able to score off the dribble. But there were also times when they ran into trouble, because they held onto the ball too long.

Play 1. Walker comes off a Theis screen, dribbles into the crowd, and gets the ball knocked out of his hands by Siakam. He’s able to recover, but the possession turns into a Tatum iso vs. Kyle Lowry and a tough, mid-range shot late in the clock.

Play 2. Tatum gets a screen from Theis and has open teammates on the wings, but keeps the ball, tries to draw a foul on Gasol, and chucks up an ugly shot.

Play 3. Tatum has three defenders in front of him after he gets a screen from Williams, and Walker is open one pass away. But Tatum tries to back his way into a crowded paint, and his late pass to Williams sails out of bounds.

Play 4. Walker rejects Williams’ screen and runs into Lowry helping off the strong side corner. When he keeps dribbling, VanVleet recovers to take the ball away.

“The pass is certainly king against the teams that can really get up into you, that really help, that are active with their hands” Stevens said Monday. “When we turned it over yesterday, a lot of it was when we had the ball too long. We’ve just gotta make the right reads quickly.”

The Adjustment: When the Raptors switch

At the start of the fourth quarter on Sunday, with Serge Ibaka at the five, the Raptors were able to flatten the Celtics out a little by switching all ball screens for a few possessions.

When Marc Gasol checked back in (and with Ibaka still on the floor), the Raptors went to their 2-3 zone. When they went back to man-to-man, they didn’t switch ball-screens with Gasol.

The Raptors had bigger issues on offense than they did on defense in Game 1, despite allowing the Celtics to make 10 corner 3s for the second time in August. Toronto’s 94 points on 104 possessions was their third worst offensive performance of the season.

But the Celtics were able to move the ball and find those open shots in the corners. Boston’s film session on Monday should also have reinforced the benefits of getting rid of the ball quickly. So we could see more switching and/or more zone from Toronto in Game 2 on Tuesday (5:30 p.m. ET, ESPN).

They weren’t the No. 2 defense in the league without mixing things up quite a bit.

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John Schuhmann is a staff writer for NBA.com. You can e-mail him here, find his archive here and follow him on Twitter.

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