As you know by now, the Boston Celtics were beaten 121-113 by the Detroit Pistons on Opening Day of the NBA season. It was an embarrassing and historic loss for the Celtics, who are expected to contend for an Eastern Conference top seed this season.

And while Jayson Tatum's 6-of-23 shooting performance is likely stealing a lot of the headlines and airtime in Boston, there is another painfully obvious conclusion that needs to be drawn from this contest.

Look, we know that the Celtics are a perimeter-oriented team that is centered around their ability to shoot the 3-ball, but still, this team has invested a lot in the interior and those guys didn't perform on Tuesday.

Mitchell Robinson, who was signed to a three-year deal worth nearly $50 million this offseason, scored just four points in 18 minutes. He also had only three rebounds.

Neemias Queta, who the team gave a contract extension in the offseason, had just three points in 22 minutes. He had only four rebounds.

And Luka Garza, who has the ability to stretch the defense with his jump shooting ability, had only two points in eight minutes. He had two rebounds.

In total, those three Celtics big men had just nine points and nine rebounds. That's not enough for the amount of money invested in the group (more than $100 million in total).

Even if you don't think the Celtics need their big men to be scorers, they do need them to be rebounders. And the C's were out-rebounded by 10 in this game.

That's basically unacceptable for this group.

So yes, Tatum needs to play better and score more, but the interior players have to do their part as well. They'll get a chance on Friday night at 7 p.m. ET against the New York Knicks at TD Garden. That will be the home opener for the Celtics.

The opener wasn't all negative, however. Paul George, acquired this offseason from the Philadelphia 76ers, had a historic debut. The veteran, who has just started his 17th NBA season, went for 38 points and he was 7-of-12 from 3-point range.

While George can't be expected to play every single game, or always at this level, he can be a big part of this team as it looks unlock a new identity in the wake of the Jaylen Brown trade.