Doc Rivers' tribute to Dirk Nowitzki on Monday night in Los Angeles started out with a lot of confusion. After all, why would the Clippers' coach call a timeout with nine seconds remaining in the game, uncontested possession of the basketball and his team up by nine points?

Well, it became clear pretty quickly. 

Rivers grabbed the microphone from the scorer's table and delivered a tribute to Nowitzki over the Staples Center PA system. Rivers beckoned the crowd to stand up and give an ovation to the Nowitzki, who may have been playing his final game at the venue. 

Rivers called the 40-year-old Nowitzki "one of the greatest of all time" as coaches, players and fans saluted the veteran big man. It was clear that Nowitzki appreciated the gesture on the court, and he confirmed as much after the game.

"It was sweet. I'm really appreciative," Nowitzki said after the Mavs' loss to the Clippers, via ESPN. "At first, I was like, 'Why is Doc calling a timeout? What's he doing with [9.4] seconds left? What's he up to?' Then he grabbed the mic. I didn't really understand much, but that was really humbling. That was an emotional moment."

Also appreciative of the gesture was Mavericks head coach Rick Carlisle. 

"It was one of the greatest things I've seen," Carlisle said. "I know there will be more moments similar to that, but this was an original. I've never seen something like this."

Nowitzki played in his 1,500th career NBA game on Monday, recording 12 points and five rebounds in a season-high 26 minutes of playing time. He hasn't yet officially announced plans to retire after this year, but he's received special ovations in several buildings this year (plus an honorary All-Star roster spot alongside Dwyane Wade, who has announced plans to retire) on what is presumed to be his unofficial retirement tour, which will continue on Wednesday when the Mavs face the Pacers (8:30 p.m. ET -- Watch on FuboTV with NBA League Pass add-on). 

All of this might look pretty awkward if Dirk decides he wants to come back for more, but for now it's an awesome and unique gesture by Rivers for one of the best players of this generation.