* Thursday on TNT: 76ers vs. Celtics (8:30 ET)

The Eastern Conference semifinals series between the Boston Celtics and Philadelphia 76ers is fun for a lot or reasons, including the history of the two franchises, the future of all the young talent on the two rosters, and the Jayson Tatum vs. Markelle Fultz question, specifically.

And though both of these teams ranked in the top three defensively and in the middle of the pack on offense, it’s also a contrast of styles, apparent with the pace that both teams played at in Game 1.

On Monday, the Celtics had one more possession (95) than the Sixers (94). But, according to Second Spectrum tracking, Boston had the ball for almost six more minutes than Philly did.

Having the ball longer isn’t necessarily an advantage. In fact, it may be a disadvantage more often than not. League-wide, effective field goal percentage is highest in the first six seconds of the shot clock and goes down as the clock does.

Defenses want to force those shots in the last six seconds of the clock and offenses want to avoid them. In Game 1, the Sixers took just three shots in the last six seconds of the shot clock.

The Celtics? 24.

And they were 13-for-24, including 6-for-10 from 3-point range, in the last six seconds of the shot clock. The 24 attempts was almost double their regular-season average of 12.6 per game. The Celtics took 15 percent of their shots in the last six seconds of the shot clock, right around the league average, in the regular season.

But the playoffs have been a different story. In their eight games, the Celtics have taken 28 percent of their shots in the last six seconds of the shot clock, by far the highest rate in the postseason (the Cavs have the second highest rate at 23 percent).

The Celtics have become comfortable living late in the clock. And more than anything, it’s been out of necessity.

For one, the Celtics don’t have Kyrie Irving, the guy on their roster with the most ability to generate good shots for himself. In many cases, especially against switching defenses, the Celtics go late in the clock because their early-clock pick-and-rolls don’t create enough of an advantage to produce an open shot.

The opponents have also had something to do with it. Priority No. 1 against the Milwaukee Bucks? Keep Giannis Antetokounmpo out of transition. Priority No. 1 against the Sixers? Keep Ben Simmons out of transition. Playing slow and deliberate is a strategy against particular opponents. The Celtics led the first round in time of possession, and they’re on their way to doing it again in the conference semis.

Of course, 13-for-24 and 6-for-10 from beyond the arc (an effective field goal percentage of 67 percent) is unsustainable. The Celtics had an effective field goal percentage of 47 percent in the last six seconds of the shot clock in the first round, and that was better than all but one team (Cleveland – 49 percent) that shot in the last six seconds in the regular season.

Both of Aron Baynes’ 3-pointers in Game 1 came late in the clock. Shane Larkin, 7-for-26 on pull-up 3-pointers in the regular season, hit a step-back three with two seconds on the clock late in the third quarter. The Celtics obviously can’t depend on shots like that going forward.

But they can depend on Al Horford, who, time after time on Monday, was patient and under control in late-clock situations.

In some cases, Horford had the ball in his hands, and worked to manufacture a shot, against Dario Saric…

or against Joel Embiid….

He also drained a late-clock jumper off penetration from Terry Rozier. And in one late-clock situation, a timely cut from Horford drew enough attention from the Sixers’ weak-side defenders to free Rozier for a catch-and-shoot three.

There’s a lot of young talent in this series, but the experience and patience of the Celtics’ veteran big man made all the difference in Game 1. The best way to keep your opponent out of transition is to execute offensively, and the Celtics do that much better when Horford is in the game. Through eight playoff games, they’ve scored 110 points per 100 possessions with him on the floor and just 102 with him off the floor. In the regular season, those numbers would have ranked sixth and 27th in the league, respectively.

Game 2 on Thursday (8:30 p.m. ET, TNT), promises to be a lot different than what we saw in Game 1. The Sixers have some mistakes to clean up and may change their defensive assignments so that J.J. Redick isn’t defending Jayson Tatum. That’s easier to do if Jaylen Brown is still out (he’s listed as doubtful with a strained hamstring) and Marcus Smart remains in the starting lineup. The Celtics had success on drives against both Redick and Marco Belinelli (scoring 21 points on 12 possessions) in Game 1.

Watched the Celtics' 34 drives (via Second Spectrum) from Game 1. Definitely had good success vs. Redick & Belinelli, though Rozier wasn't afraid to take Simmons off the dribble either. pic.twitter.com/HPjZ9AXq6s

— John Schuhmann (@johnschuhmann) May 2, 2018

The Celtics probably won’t shoot as well as they did on Monday. But pace will continue to be a battle in this series and it’s clear that Boston has become comfortable playing late in the clock.

* * *

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

The views on this page do not necessarily reflect the views of the NBA, its clubs or Turner Broadcasting.