One of the starkest advantages in the first round of the playoffs for the Knicks was a domination on the offensive glass by Mitchell Robinson and his teammates.

As a result, the Knicks averaged 18.2 second-chance points per game in their five-game elimination against the Cavaliers and their primary big men Jarrett Allen and Evan Mobley.

That number dropped to 11 in Sunday’s second-round opener against All-Star center Bam Adebayo and the Heat, however, with the Knicks’ securing only eight offensive rebounds — and two by Robinson in 31 minutes — in a 108-101 loss at the Garden.

“They play two different roles, two different styles of play,” said Robinson, who had a whopping 11 offensive boards in Game 5 in Cleveland. “Bam brings it up, Jarrett didn’t. So you gotta be aware of that. Just gotta get back to the film and learn.”

The 7-footer also appeared to suffer a hard fall in the first half, landing on his hip.

He acknowledged afterward that he’s “very” banged up and required “some treatment,” before adding “I’m gonna be alright” for Game 2.

The Knicks did hold a 41-36 overall rebounding edge in Game 1, with Robinson and Heat star Jimmy Butler snaring a game-high 11 apiece.

Robinson, backup center Isaiah Hartenstein and Josh Hart attempted to crash the offensive glass more in the second half, but they couldn’t corral many rebounds, leading to three long outlet passes from Kevin Love to Butler for easy baskets.

“Boardman gets paid; it’s not that easy to keep that 7-1 off the glass, 270 [pounds] whatever he is,” Love said, referring to Robinson. “But I think we sent bodies at him, and other guys clean up, or myself, when Bam’s on him. Yeah, I think that’s part of it.

“But game plan? I don’t know. We certainly want to get easy triggers, easy buckets, buckets in transition if we can. But, you know, we felt like that just worked for us. We’ll see what happens.”

Obi Toppin, who finished with eight rebounds, said that allowing Love’s outlet passes was “definitely miscommunication” by the Knicks.

“We can’t allow those free buckets,” Toppin said, “so we’re gonna fix that.”