Celtics passed this test with physicality

What impressed about the Celtics’ 107-99 win over the Chicago Bulls were the multiple efforts, the fortitude shown against a team that has given them fits over the past few years.

The Bulls have a losing record and would be a play-in participant if the season ended today, but they are not a team the Celtics want to see in the first round. Chicago matches up too well with them.

Yet a team that has been guilty of taking opponents lightly or easing into games did neither Monday at TD Garden. The Celtics were prepared for an arduous struggle, got one, and still have the NBA’s best record at the halfway point.

The Celtics matched Chicago’s physicality. Seven players had at least five rebounds, including Jayson Tatum with a team-leading eight. The Celtics’ toughness has been questioned over the past few months, especially against bigger teams.

But with Robert Williams back in the starting lineup, they looked back to normal, back to NBA Finals form.

It was one of the more important wins of the season because it earned zero style points. The Celtics missed 30 of their 41 3-pointers and allowed Zach LaVine to score 15 fourth-quarter points as the Bulls sliced a 16-point deficit to two.

Being pushed late in games, when the opposing player can’t be stopped, is exactly what the Celtics needed.

“I thought this was one of our better wins, one of our complete wins because of our mind-set and our toughness,” Celtics coach Joe Mazzulla said. “Regardless of the result at either end of the floor, I think we kept a certain body language and a certain focus about us, a togetherness, a commitment to the details, and it was really fun to watch the guys do that.”

These are the intangibles the Celtics lacked this time last year, when they were 20-21 at the midway point. They are 29-12 this time around, keeping their promise that they would begin this season stronger, with more focus and less selfishness.

The game’s pivotal play came on a Tatum assist, when Patrick Williams and Alex Caruso converged on him with the Celtics up two and less than 30 seconds left. Tatum could have attempted to split the two on a drive, but he found an open Al Horford behind the 3-point line because Nikola Vucevic made the decision to cover Grant Williams in the paint. With his easy motion, Horford canned the 3-pointer for a 5-point lead. Maybe a few years ago Tatum takes on the entire Chicago defense, or at least feels like he has to, but this time he made the simple play.

“Trusting your teammates in those situations,” Tatum said. “It’s all about making the right play, whether that’s for somebody else or for myself. Credit to Al, that’s a big-time shot.”

The Celtics undoubtedly had this game circled on the schedule, because the Bulls had beaten them badly twice in Chicago and it was the first home game after a southwest road swing.

And they didn’t exactly end the road trip in dominating fashion by nipping the downtrodden Spurs.

But as we’re learning this season, bad losses or unimpressive wins are part of the journey, even for elite teams. The Bulls snapped the Nets’ 12-game winning streak, then followed up with a 14-point win that ended Philadelphia’s 11-game home winning streak. Against Boston, DeMar DeRozan left in the third quarter with a quadriceps strain but LaVine took over before the Celtics reacted by holding him scoreless for the final 2 minutes, 17 seconds.

The Celtics were tested late and they passed. They are a more mature team than last season, one that has learned from their humbling NBA Finals experience. It’s their third win since that Oklahoma City debacle and they appear connected and cohesive, even with starting point guard Marcus Smart out with a knee injury.

“I think we’ve done decently well,” forward Grant Williams said of the season’s first half. “Definitely we’ve had some drop-offs in some games where we shouldn’t have performed the way we did.

“We definitely can’t say we were perfect by any means. I think we’re doing a good job of making sure we’re responding the right way, keeping the same mentality, keeping the same cheer and joy for one another, and getting back to really who we were at the beginning of the season.”

The Celtics’ early-season goal was to build enough equity to avoid having to make a historic second-half run as they did last season. They were exhausted entering the playoffs and the strenuous run caught up to them in the NBA Finals.

The key to the second half will be learning to win more consistently when the threes aren’t falling and the adversity is thick.

The Bulls are better than their record, especially against the Celtics, and were hardly daunted by the league’s top team.

The good news is the Celtics weren’t daunted by that challenge. They punched first, led most of the game and made winning plays to seal it.

“I thought we had a complete game from our team,” Mazzulla said. “We really focused on our mind-set, our toughness, and our execution. I thought we’ve handled success well. I thought we’ve handled failure well. We’re going to be tested with both throughout the year and it’s just a matter of how we respond to it.”