BOSTON – Billy Donovan isn’t looking for cute nicknames to hand out to his bench players.

No, that’s not how the Bulls coach works.

Floor burns, some bruises, loose balls being corralled at any cost? That’s what Donovan can get behind. Nicknames? Save those for a different coach.

That’s why Donovan has been challenging his second unit for weeks, trying to get them to buy into the idea that doing the little things wins games, and winning games in that fashion means more playing time.

Message heard.

Down four entering the final quarter against the defending world champions on Thursday, Donovan watched reserves like Lonzo Ball, Talen Horton-Tucker, Jalen Smith and Julian Phillips, along with current starting guard Ayo Dosunmu, make the game grimy.

Whether it was Dosunmu diving on the floor for a 50-50 ball, Phillips defending Jayson Tatum one-on-one and not flinching, Horton-Tucker using his physical frame to grab an offensive rebound and give his team an extra possession, or Ball just doing Ball things, it worked.

And it worked so much that Donovan watched the deficit go to a nine-point lead, allowing him to rest his one-two starting punch of Nikola Vucevic and Zach LaVine longer than usual in that final stanza.

“Billy challenged us a little bit early in the season, the second unit, guys off the bench, to come in and try and provide some type of energy or spark,” Horton-Tucker said. “It feels like guys are starting to lock into that, understanding who is going to have the ball in their hands, who can be live, who is going to make the right plays defensively. But just having a standard for all the guys that come off the bench is important, making sure that everyone is on point.”

Because when they are the Bulls look like a different team. No one appreciates that more than LaVine.

“That second unit at the beginning of the fourth quarter did a great job,” LaVine said. “Zo out there, Julian, THT, ‘Big Sticks (Smith),’ offensive rebounds, kick-outs, down on the floor, big defensive stops, they gave our first unit more of a break and expanded the lead. They did a good job.”

Which is why Donovan isn’t done issuing challenges to the group.

Because the Bulls are an undersized roster, playing with pace has been just one counter to that size difference on most nights. Donovan, however, also needs the group – starters and reserves – to play with a high level of physicality.

That’s been the frustration for the coach this season.

There are times they flash the idea of uglying a game up, but far too often it’s been inconsistently consistent.

“When you’re trying to make a point, (Thursday) shootaround, film, whenever it is, and (they see) we’re not blocking out and then it starts again (like it did in the first half against Boston), ‘We’re going to have to get this resolved,’ “ Donovan said. “I thought the physicality, we kind of meted better in that second half and the fourth quarter, but that’s what happens when you play against a team that won a world championship.”

Which was Donovan’s message to his players after the game.

Doing the little things can’t just take place when playing a high-profile team like the Celtics. It has to be done on a nightly basis no matter the team sitting on the opposite bench.

Fortunately for the coach he’ll have a chance to get that message to stick with the Bulls and Celtics playing a Saturday rematch, this time at the United Center.

“When you’re playing in a game like that, hopefully we can find ways to learn, ‘Hey, we’ve got to do that consistently,’ “ Donovan said. “It doesn’t matter who you’re playing, for us it still has to be a priority. I hope it does stick in and clicks.”