Why pace matters if the Celtics want to close out their series

The Boston Celtics held a 66-58 edge over the Atlanta Hawks at halftime of Game 5 on Tuesday, but the stat everyone was raving about at the time looked more lopsided.

Boston was up 20-0 in fast break points and smoking the Hawks in transition. According to Cleaning the Glass, they were adding 14 points per 100 possessions with their transition buckets, helping boost the offensive floor as they appeared on track for a victory. They then managed just four fast break points in the second half, underscoring the brutal late-game stagnation viewers have recognized all too well from the regular season.

Coach Joe Mazzulla even referenced the negative tempo shift that led to the loss in his postgame presser.

“I think it’s more we just lost our pace a little bit on the offensive end — partly on, you know, me trying to make sure we run a good play,” Mazzulla said. “And we talked about playing faster down the stretch, and I thought we just lost some of our pace, which allowed them to pressure us and get into passing lanes.”

Pace isn’t a new improvement area with this Celtics team (or past teams). During the regular season, they got out in transition on just 13.8% of their plays, tied for the fourth-lowest rate in the NBA. However, Boston was a respectable 12th in the league in transition scoring efficiency, but it hardly mattered because the team rarely sought out those chances.

Boston’s elite, third-ranked halfcourt offense put up 103.4 points per 100 possessions in the regular season; their middling transition offense was still far more effective (127.5).

Pushing the pace isn’t a magic ticket to success. The Philadelphia 76ers just swept the Brooklyn Nets while hardly accomplishing anything on fast breaks. But among the top eight playoff teams most frequently getting out in transition, seven (the Lakers, Kings, Knicks, Suns, Heat, Hawks, and Grizzlies) have advanced to the next round or at least pushed their series to six games.

The Celtics struggled to do so through four games, and then in the first half of Game 5, they put on a clinic.

Boston picked up one steal in the entire contest. When they succeeded in transition, they beat the Hawks after misses. Jaylen Brown gets out and running quickly here, and once he notices no Hawks defense behind De’Andre Hunter, he attacks the matchup. Brown decisively went at perceived mismatches for most of the game, also blowing past guys like Jalen Johnson and Clint Capela with his downhill speed and…