WASHINGTON, D.C. — His mannerisms, in this venue, against this opponent, were familiar.

Osun Osunniyi wore a half-scowl after each rim-rattling dunk. He puffed his chest after every punishing block. He pumped his fists after drawing a late basket and the foul.

His gestures were just as demonstrative as they were last March because Osunniyi was just as dominant.

Ten months earlier, the 6-foot-10 center had played his best game to date, totaling 18 points and 16 rebounds in a 64-58 victory in the nation’s capital. On Sunday, he did the same, recording a career-high 20 points on 8-for-8 shooting, nine rebounds and five blocks to help Bona to an Atlantic 10-opening 71-66 win over George Washington before a thin crowd of 2,259 inside the Charles E. Smith Center.

In a tight game throughout, Bona (9-5,1-0) used an 11-1 run midway through the second half to give itself a breathing room. Clinging to a 53-52 lead with under seven minutes remaining, Osunniyi tallied five-straight points, including his and-1, to help seal it.

“Coach (Mark Schmidt) says all the time, our best players have to play great and our role players have to do their job and give us a spark,” Osunniyi said.

“Coach has confidence in me and knows that I have to play my A-plus game in order for my team to win, so that’s just me having confidence in myself and my game, and the coaches having confidence in me to know that if I play really well, we have a chance to win the game.”

Behind Osunniyi, Bona won in the Smith Center for the second-straight year after having previously lost 17 of 18 in Foggy Bottom. In those two contests, ‘Shoon averaged 19 points, 12.5 rebounds and four blocks.

What is it about playing the Colonials that has led to that kind of success? It’s more than just a favorable matchup, Schmidt said.

“He’s a good player, the 13th-year coach said plainly. “It doesn’t matter where you play, if you’re a good player, you can play anywhere. Kyle (Lofton) did a good job of delivering the mail, too.”

Lofton had another splendid game from the floor, totaling 17 points and eight assists. Many of those came on entry passes to Osunniyi, who finished for easy layups and dunks.

According to Osunniyi, Schmidt saw an opportunity for Bona to capitalize with ball screens, “so we just kind of went to our ball screens a lot and it worked. A two-man game.”

The dynamic sophomore duo wasn’t the only difference-maker for the Bonnies, however.

Matt Johnson was given his first meaningful minutes since November due to the absence of Jaren English, who sat with concussion-like symptoms suffered Friday in practice. The junior guard made the most of them, scoring a Division I-high 12 points, including seven-straight in the first half and a key 3-pointer with 4:03 left to give Bona a 61-54 advantage.

Bobby Planutis also came up big, tallying 13 points, nine of those coming in the second half to help keep his team afloat.

The two reserves helped the Bonnies offset the loss of one starting guard and no points from another (Dominick Welch).

“(Matt) got an opportunity to play, he was prepared, he made a big difference in the first half,” said Schmidt, whose teams are now 9-4 in A-10 openers. “He gave us a big lift coming off the bench. “Bobby did a really good job, especially in the second half, and that was the difference.”

Of what those performances could mean for those players, and Bona, moving forward, Schmidt added: “It gives them confidence, it gives us confidence as a coaching staff that (Johnson) could be put in that situation on the road and have some success … us winning a game without Dom scoring a point is a good sign.”

After struggling to score in the first half, and trailing 30-28 at the break, Bona had a much better final 20 minutes, shooting 59 percent (16-of-27). It also checked each box in Schmidt’s well-documented trifecta: It defended, holding the Colonials without a truly meaningful field goal down the stretch, held a 33-27 advantage on the glass and committed just eight turnovers.

That and an effective half-court offense helped the Bonnies pull away from transitioning, and struggling, GW (6-8, 0-1), which had made enough 3-pointers (9-of-27) to remain within striking distance.

“That’s how you win,” Schmidt said of the “trifecta.” “We’ve only won one game when we’ve been outrebounded — Rutgers.

“That’s a huge key, and to keep our turnovers under 10, then they don’t get out on the break, we play a halfcourt defensive game, and that’s to our advantage.”

On Day 1 in A-10 play, Bona — which has won four of the last five over the Colonials — was on the road, minus a starter (English remains day-to-day) and in a one-score game throughout, as Schmidt predicted beforehand.

How big was it to come into the Smith Center and leave with a win?

“We know that if you want to win in the A-10, you’ve got to steal some games on the road and protect home court,” said Osunniyi, whose outing included an impressive play in which he’d gotten beaten by GW’s Chase Parr, but still used his long reach to reject the freshman center’s shot. “So we got one, (and) we’ve got another good opportunity to (steal another) at George Mason, they’re a really good team.

“So right now, we’re on the right track, we got the first one, now we have to get the second one on Wednesday.”