BOSTON — Jaylen Brown, Gordon Hayward, Terry Rozier and Aron Baynes all could start for a number of NBA teams. All have started for the Boston Celtics at one point or another. And now all four make up one of the NBA’s most terrifying second units.

Just ask the New York Knicks.

With Brown back in action Thursday after missing four games with a back injury, the Celtics got their first look at what many expect will be their normal rotation going forward.

They had to have liked what they saw, especially from Brown.

The third-year guard was aggressive from the moment he stepped on the floor midway through the first quarter. Brown played his best game of the season, totaling 21 points on 7-for-10 shooting while also going 7-for-9 from the free-throw line. He attacked the rim off hand-offs and cutting action, using his strength and athleticism to get to the tin rather than settle for outside jump shots.

While Baynes left early in the first quarter Thursday with a sprained ankle, the rest of the bench combined to score 50 points in Boston’s 128-100 stomping of the Knicks at TD Garden.

Kyrie Irving, who poured in a game-high 22 in the win, noted how the second unit only will continue to improve as their chemistry grows with Brown now coming off the bench.

“Just being aggressive, that’s who they are,” Irving said of the bench unit. “Having some of the starters out there, I think I finished the quarter until about under two and then Terry came and got me and they continued to push the pace. And that second unit still has to develop their chemistry as well as they get Jaylen on that second unit. I think they’ll look great. We probably have one of the most talented second units in the league if not the best talent. Now we just all put it together and play a full 48-minute game where our first unit, second unit — we all go at each other in practice so it’d be great to see them develop but they played a great game tonight.”

Brad Stevens’ decision to stick with the Marcus Smart and Marcus Morris in the starting lineup appears to be the correct one for now.

The Celtics’ offense through 20 games was stuck in the mud with Brown and Hayward occupying the starting lineup for much of that time. Surrounding Irving and Jayson Tatum with the toughness and grit of Smart and Morris, two players who have defined roles as complementary players, has allowed Boston to get off to faster starts by focusing the offense on running through the star guard and the young forward in the opening minutes. It also has made the second unit much more dangerous, as Brown, Hayward and Rozier each are capable of taking over a game at any moment.

Credit to Brown and Hayward for taking their bench roles in stride to become the lynchpins of a terrifying bench mob that will no doubt overwhelm a number of opponents.

If the two swingmen can continue to jell with the second unit, Boston’s new normal will become the NBA’s worst nightmare.

Thumbnail photo via Greg M. Cooper/USA TODAY Sports Images