"Once [Antetokounmpo] gets momentum and he gathers, there's so much he can do," said Matthew Dellavedova, who assisted on the dunk. "I know he's got Baynesy a few times [this season], but Baynesy, I know he doesn't care. He's just trying to help his team win."

Antetokounmpo's poster was the lasting image of Milwaukee's dominant Game 3 triumph that trimmed Boston's series lead to 2-1. But it was merely the latest instance in which Baynes put his team ahead of his own well-being while trying to contest a would-be dunker.

By the time he looked up, it was too late.

Baynes was sitting on the TD Garden parquet floor trying to put on the left shoe that had just popped off while trying to take a charge from Oklahoma City Thunder star Russell Westbrook.

But the Celtics scored so quickly at the other end of the floor, that before Baynes knew it, Westbrook had the ball again and was racing his way.

"We made eye contact when he was at about half-court," Baynes said. "I knew he was coming at me."

So did everyone else on the court. Carmelo Anthony's eyes darted from Westbrook to Baynes and, sensing what was about to happen, Anthony cleared the runway.

Few would have blamed Baynes if he simply covered his head or rolled out of the way of the speeding reigning MVP. But as Westbrook raced past Celtics rookie Jayson Tatum at the top of the 3-point arc, Baynes did the only thing that made sense to him -- he scrambled to his feet then leapt to contest as a full-throttle Westbrook launched into him.

The force of their mid-air collision knocked Baynes from just inside the charge circle to below the baseline. A desperation swipe by Tatum might have caused Westbrook to lose control of the ball going up and prevented Baynes from enduring an undesirable career highlight.

Instead, the sequence displayed what Baynes has brought to the Celtics all season: A sturdy backline defender who is utterly fearless in giving up his body despite opponents routinely attempting to put him on a poster.

"My job is to try to make every shot attempt of the opponent's as tough as I can. If that's me putting my body on the line then each time I'm going to step up and do it," Baynes said. "It's fun for me. I like it when guys are focused on [trying to dunk on] me because then they're not focused on their game."

Baynes logged only 18.3 minutes per game during the 2017-18 season, but he started most halves alongside All-Star Al Horford in Boston's frontcourt, and there was an obvious difference in the Celtics' defensive intensity when Baynes was on the floor.

The Celtics owned a defensive rating of 97.0 with Baynes on the court. That was the best individual defensive rating for a qualifying player in the NBA this season and it was also 4.5 points per 100 possessions better than Boston's league-best defensive rating of 101.5 overall.

"We made eye contact when he was at about half-court. I knew he was coming at me."

Individually, Baynes allowed a mere 0.739 points per play, according to Synergy Sports data. Among the 207 NBA players with at least 500 possessions defended this season, Baynes ranked No. 1 in points allowed per possession (and by a healthy margin with Golden State's Andre Iguodala second at 0.768 points allowed per play).

It's why Celtics coach Brad Stevens calls Baynes an "elite" NBA defender. And it's why Horford, maybe Boston's top candidate to earn All-Defense honors this season, can't gush enough about the Australian giant who has drastically eased the load up front this season.

"He makes my job so much easier," said Horford, who ranks sixth on that same list of qualifying defenders while allowing 0.799 points per play, per Synergy.

"People always obviously talk about our defense and how great it is, but [Baynes'] impact is what has put us in this position. And nobody talks about him for Defensive Player of the Year and all those things. I'm not a numbers guy, but I think his impact goes a long way.

"Honestly, he's the ultimate team guy."

And each time Baynes goes up to contest a dunk, he proves that again ... and again.

When players, such as Giannis Antetokounmpo, see Aron Baynes patrolling the paint, it's go time. Bob DeChiara-USA TODAY Sports

Jaylen Brown was one of the first teammates to reach Baynes as he laid face-down under the basket.

Baynes had just put his life in jeopardy when he contested an Antetokounmpo dunk attempt, and now Baynes needed a minute to, as he would later quip, make sure all his parts were in the right place.

A Dellavedova screen had pinned both Horford and Shane Larkin, allowing Antetokounmpo a free run at the hoop late in the first quarter of an October meeting between the Celtics and Milwaukee Bucks. Baynes left his man on the opposite block and rose up as the Greek Freak reared back for a ferocious tomahawk.