This will be the 20th time that the Boston Celtics and Philadelphia 76ers are meeting in the postseason. And it won’t be the last.

When the season started, it was pretty clear that the Celtics would be here. It wasn’t so clear when they lost Gordon Hayward for the season less than six minutes into their first game, and it became even less so when they lost Kyrie Irving shortly before the playoffs began. But here they are, with an elite defense and young talent that’s exceeding expectations.

The Philadelphia 76ers know a little about that. At first, they wanted to make the playoffs. Then they set their sights on a top-four seed. Now, they’ve won 20 of their last 21 games, looking like the best team in the Eastern Conference as they’ve done it.

This series has a lot of history, along with a very bright future.

• Celtics-Sixers series hub | John Schuhmann’s series preview

Here are some statistical notes to get you ready for the Eastern Conference semis, with links to let you dive in and explore more. Game 1 is Monday at 8 p.m. ET on TNT.

Pace = Possessions per 48 minutes

NetRtg = Point differential per 100 possessions

Boston Celtics (55-27, 4-3)

First round: Beat Milwaukee in 7 games.

Pace: 94.2 (13)

OffRtg: 106.1 (10)

DefRtg: 107.7 (11)

NetRtg: -1.6 (9)

Regular season: Team stats | Advanced splits | Player stats | Player shooting | Lineups

vs. Philadelphia: Team stats | Advanced splits | Player stats | Player shooting | Lineups

Playoffs: Team stats | Advanced splits | Player stats | Player shooting | Lineups

Celtics first round notes – Team:

1. Only 10 percent of their possessions have been in transition, the lowest rate in the playoffs so far.
2. Allowed only 7.0 second chance points per game, fewest in the first round.
3. Worst second quarter team in the first round, getting outscored by 28 points per 100 possessions in the second period. Were a plus-24 in the first quarter and a plus-32 in the third, but were outscored by 47 points in the second against Milwaukee.
4. Four of their seven games were within five points in the last five minutes. Both the Celtics and Bucks shot 50 percent or better on clutch shots.
5. Possessed the ball for 48 percent of their total minutes, the highest rate in the first round. Averaged 12.9 shots in the last four seconds of the shot clock, most in the first round.
6. Rank third in ball movement (342 passes per 24 minutes of possessions), but 14th in player movement (9.9 miles traveled per 24 minutes of possession) in the playoffs.

Celtics first round notes – Individuals:

1. Outscored the Bucks by 45 points in 154 minutes with both Jaylen Brown and Jayson Tatum on the floor, and were outscored by 35 points in 169 minutes with only one of the two on the floor.
2. Brown had his shot blocked 12 times, most in the first round.
3. Al Horford had a free throw rate (FTA/FGA) of 0.425, up from 0.159 in the regular season. That was the biggest jump among players with at least 300 field goal attempts in the regular season and at least 50 in the first round.
4. Greg Monroe (18 percent) and Aron Baynes (17 percent) had the two highest offensive rebounding percentages among players who averaged at least 10 minutes per game in the first round.
5. Marcus Morris shot 45 percent (10-for-22) from 3-point range, up from 37 percent in the regular season. That was the third biggest jump among players with at least 200 3-point attempts in the regular season and at least 20 in the playoffs thus far.
6. Terry Rozier (8-for-13) was one of two players to shoot better than 50 percent on at least 10 corner 3-point attempts in the first round. His three clutch 3-pointers (all in Game 1) were the most in the first round.
7. Rozier traveled 1.57 miles per game on offense, the second most in the first round.
8. Tatum ranked eighth in the league in 3-point percentage (43 percent) in the regular season, but shot just 8-for-26 (31 percent) from 3-point range in the first round.
9. See Celtics-Bucks preview for regular season notes.

Philadelphia 76ers (52-30, 4-1)

First round: Beat Miami in 5 games.

Pace: 103.0 (1)

OffRtg: 109.6 (5)

DefRtg: 101.6 (3)

NetRtg: +8.0 (3)

Regular season: Team stats | Advanced splits | Player stats | Player shooting | Lineups

vs. Boston: Team stats | Advanced splits | Player stats | Player shooting | Lineups

Playoffs: Team stats | Advanced splits | Player stats | Player shooting | Lineups

Sixers first round notes – Team:

1. Only team that outscored its opponent by more than 10 points per game in the first round.
2. Best fourth-quarter team in the first round, outscoring the Heat by 31 points per 100 possessions in the final 12 minutes of regulation. In the regular season, they were the worst fourth-quarter team (minus-4.8 per 100) among those that made the playoffs.
3. Averaged 11.2 miles traveled on offense and 387 passes per 24 minutes of possession. Those were the highest marks for both player and ball movement in the first round.
4. Assisted on 68 percent of their field goals, the highest rate in the first round. Their 34 assists in Game 1 were the most for any team in a first-round game.
5. Isolated on only 2.9 percent of their possessions, the lowest rate in the playoffs.
6. Averaged 24.6 catch-and-shoot 3-point attempts, most in the first round.
7. Averaged 16.2 second chance points per game, most in the first round.
8. Allowed the Heat to shoot only 54 percent in the restricted area, the lowest mark in the first round.
9. Led the first round in aggregate bench NetRtg (plus-9.7 points per 100 possessions).

Sixers first round notes – Individuals:

1. Joel Embiid averaged 7.3 post-up possessions per game, second most in the postseason.
2. Embiid had a free throw rate (FTA/FGA) of 0.917, the highest rate among players with at least 25 field goal attempts in the playoffs.
3. The Heat shot 5-for-19 (26 percent) at the rim when Embiid was there to protect it. That was, by far, the best rim protection mark among players who defended at least four shots at the rim per game in the first round.
4. The Sixers scored 121.5 points per 100 possessions with Amir Johnson on the floor. That was the highest on-court OffRtg for players that averaged at least 15 minutes per game in the first round.
5. J.J. Redick and Marco Belinelli averaged 5.15 and 5.12 miles per hour on offense, the two fastest speeds among players who averaged at least 20 minutes per game in the first round. They also averaged 4.4 and 3.8 hand-off possessions per game, most in the playoffs thus far. They shot a combined 8-for-33 (24 percent) off hand-offs.
6. Dario Saric shot just 46 percent in the restricted area, the worst mark among players with at least 20 restricted-area field goal attempts in the first round.
7. Ben Simmons was one of four players with a first-round triple-double, registering 17 points, 13 rebounds and 10 assists in Game 4 in Miami.
8. Simmons took 89 percent of his shots in the paint, the second highest rate among 59 players with at least 50 field goal attempts in the playoffs through Saturday.
9. See Sixers-Heat preview for regular season notes.

Regular season matchup

Season series: Celtics won 3-1 (1-1 in Boston)

Oct. 20 @ Philadelphia – Celtics 102, Sixers 92

Nov. 30 @ Boston – Celtics 108, Sixers 97

Jan. 11 @ London – Celtics 114, Sixers 103

Jan. 18 @ Boston – Sixers 89, Celtics 80

Pace: 100.5 possessions (per team) per 48 minutes

Boston OffRtg: 100.3 (19th vs. Philadelphia)

Philadelphia OffRtg: 94.9 (25th vs. Boston)

Individual matchups: Boston offense vs. Philadelphia defense | Philadelphia offense vs. Boston defense

Matchup notes:

1. None of the four meetings took place in the last three months. After their Jan. 18 win in Boston, the Sixers were 21-20 and in eighth place in the Eastern Conference.
2. Kyrie Irving played in each of the Celtics’ three wins, missing the Sixers’ win in Boston. Marcus Morris and Marcus Smart each missed the first meeting for the Celtics.
3. For Philadelphia, Joel Embiid missed the Nov. 30 meeting and J.J. Redick missed the Jan. 18 meeting.
4. Their 94.9 points per 100 possessions were the fewest the Sixers scored against any opponent this season. Their effective field goal percentage of 49.4 percent was their lowest mark vs. any opponent and their 19.9 turnovers per 100 possessions were their second most vs. any opponent.
5. The Celtics’ 18.1 turnovers per 100 possessions were their second most vs. any opponent.
6. Over the four games, the Sixers were a plus-10 over the first three quarters and the Celtics were a plus-33 in the fourth. Philly led the London game by 22 points in the middle of the second quarter and the Celtics outscored them, 75-36, over the next 24 minutes.
7. The Celtics outscored the Sixers by 45 points in 140 minutes with Al Horford on the floor, but were a minus-22 in 52 minutes with Horford off the floor.
8. Simmons was a minus-37, his worst plus-minus against any opponent.
9. Jaylen Brown shot just 17-for-46 (37 percent), his worst mark vs. any opponent that he played more than two games against. Simmons was the Sixer who defended him most, and he shot just 3-for-13 on those possessions, with nine of the 13 attempts coming from 3-point range.
10. Horford was the primary defender on Simmons, and the Sixers scored just 61 points on those 68 possessions, almost 21 per 100 less than their average. They also scored rather inefficiently when Horford defended Embiid. Embiid was a plus-8 in 40 minutes with Aron Baynes on the floor as the opposing center, but a minus-9 in 53 minutes otherwise.

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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