Virginia guard Malcolm Brogdon, left, talks with forward Darion Atkins during the second half against James Madison. Atkins finished with a game-high 10 rebounds. (Steve Helber/Associated Press)

The stream of James Madison fans leaving the building was increasing as quickly as Virginia’s lead Friday night, but Coach Tony Bennett nonetheless felt compelled to call his only timeout of the second half.

The impetus was an easy fast-break layup that had followed a putback jam by Cavaliers forward Darion Atkins, ultimately a meaningless sequence during No. 9 Virginia’s 79-51 season-opening win at James Madison.

This, though, was about next week, next month and the next calendar year, when the games will become tighter and the answer emerges to whether these Cavaliers can live up to lofty preseason expectations.

So Bennett pointed his finger toward Atkins, who would sum up the interaction as “Stop doing stupid stuff.” Then the coach laid into the rest of the team.

Bennett needed them to understand defensive lapses would not be acceptable. Not when Virginia’s lead reached a game-high 29 points Friday night, not when the nonconference schedule gets tougher starting next week and definitely not when the Cavaliers begin the defense of their ACC title come January.

“Our identity is getting stops and being contenders,” guard Malcolm Brogdon said. “Not taking our foot off the gas.”

It proved to be one of the few moments of drama during Virginia’s first visit to the Convocation Center since 1982, when Harrisonburg native Ralph Sampson, who sat two rows behind the Virginia bench Friday, and the Cavaliers were ranked No. 1 in the country.

For the first time since that era, fan fervor around Charlottesville has approached those levels after Virginia’s Sweet 16 run a year ago. A sizable contingent of orange-and-blue-clad fans mixed in with the home team’s purple as part of an over-capacity crowd of 6,782 on hand to watch the first sold-out James Madison basketball game in 20 years.

There were other ingredients in place to make an opening-night upset seem feasible, at least before tip-off. Virginia was one of only two top 25 teams to play a true road game Friday night, and it was without starting point guard London Perrantes and junior Evan Nolte, both suspended for a violation of team rules over the summer.

“You really couldn’t hear during timeouts, because they put us near the band,” Bennett said. “I could tell the freshmen were like, ‘What’s going on?’ They had not been in that setting.”

But in a game that proved uncompetitive for long stretches, the moments that could bear fruit in the coming weeks and months were of particular importance.

Junior Justin Anderson, a notoriously streaky shooter, hit 4 of 5 three-pointers and finished with a team-high 18 points. Forward Anthony Gill scored 15 points in 16 minutes, a key reason Virginia outscored the Dukes 36-8 in the paint. Atkins had a game-high 10 rebounds. Redshirt freshman Devon Hall added five steals starting in place of Perrantes.

The Cavaliers began the game by hitting 10 of their first 11 shots. They held James Madison to 28.3 percent shooting for the game. It didn’t help the Dukes that junior guard Andre Nation, last season’s leading scorer, was also unavailable because of a suspension.

Virginia freshman Isaiah Wilkins, the stepson of NBA Hall of Famer Dominique Wilkins, had an impressive debut, filling up the stat sheet with eight points, five rebounds and three assists. He was one of three first-year Cavaliers to play Friday, and Bennett indicated after the game that forward Jack Salt of New Zealand is a likely redshirt candidate this season.

“Coach said there were some glimpses of promising basketball,” Anderson said.

Even Bennett, though, did not get through opening night without a hiccup or two.

At one point, with James Madison’s band blaring — “trumpets and everything,” Gill said — the rest of the bench couldn’t help but start laughing when their coach became visibly frustrated that nobody could hear his instructions.

The irony was not lost on them.

“He’s always telling us to be mentally strong and stuff like that, and they definitely got to him,” Gill said.