Cavaliers guard Marial Shayok helped spark a run against East Carolina. (Amber Searls/USA Today Sports)

For 99 seconds this month in a game against East Carolina, John Paul Jones Arena was home to the Marial Shayok show.

With around 12 minutes left in the first half, the lanky junior guard spotted up on the right edge of the perimeter and rattled off three three-pointers in a row. It played out like a game of pinball — catch, pull up, launch and bounce the shot off the back of the rim and directly into the hands of Jarred Reuter, who fed Shayok from the lane all three times without missing a beat. The third shot circled the rim before falling out as the fans groaned and Shayok jogged back upcourt, shaking his head and smiling as he went. Thirteen seconds down.

Just over a minute later, Shayok redeemed himself by sinking a three-pointer that set off Virginia’s 31-6 run to close out the opening period.

“Just gotta have a short memory,” Shayok said afterward.

Comical though it was, the rapid-fire three-point shooting was a taste of what’s long been in the works for Shayok. In his third year at Virginia, he is finally coming into the sixth-man role Coach Tony Bennett had pictured.

“Marial could start, you could make a case, and this will all evolve – but right now, that’s one thing I challenged with Marial,” Bennett said. “I said, ‘Let’s be a sixth man that comes off, gives us some energy and a spark.’ And I thought defensively he was good, and he gave us those baskets. He can play, manufacture his own shots.”

This season is shaping up to be an important one for the sixth man at No. 12 Virginia (10-1), which begins ACC play Wednesday at No. 6 Louisville. The team moved through its nonconference slate with a spotty shooting record, and during those games, a trend emerged: It takes just one player to step up and get hot to shift the Cavaliers’ offense into motion.

The most recent example was Virginia’s win against California, which required 14 points from freshman sharpshooter Kyle Guy in the second half. Guy, who does not start, elevated Virginia’s paltry 32.3 shooting percentage in the first half to 46.2 percent in the second. Against East Carolina, the catalyst was Shayok.

The quiet guard from Ottawa isn’t as well-known for his shooting, but Shayok has nonetheless had a strong showing through the first 11 games of the season, averaging 8.3 points in 17.5 minutes off the bench. He’s the third-leading scorer on the team, behind senior point guard London Perrantes, who averages 10 points per game, and Guy, who contributes 9.4 . And though Shayok might not be the most reliable spot-up shooter, he has gained confidence in his scoring ability and grown into an aggressive defender.

“He didn’t show a lack of confidence,” Bennett said of Shayok’s trio of three-pointers. “He took three threes in about eight seconds, and they all actually were good shots. Then he took a couple more, so I was glad to see that, actually.

“Marial’s wired to score. He always does a good job of getting those shot attempts up. . . . He can touch the paint; he can manufacture his own shot off the dribble probably as good as any of the guys we have. He plays hard defensively. He’s really a competitor. I think he’s improved.”

Shayok learned to trust himself more as a shooter in the offseason, mainly through countless shooting drills. Another central element of his progress required a different kind of work — it took him two years, but the 6-foot-5 guard finally learned to stay away from cookies and pizza, so much so that he reported for practice in the fall having shed 20 pounds. He now weighs 196.

Center Jack Salt has watched his longtime roommate turn into a gym rat before his eyes.

“He works out so much,” Salt said. “He was always in the gym this summer and all this season.”

Being lighter means Shayok moves better, which has helped his confidence as well. The way he sees it, he has put in too much effort not to go for three three-pointers in a row – despite having one of the team’s lowest three-point-shooting percentages – or put a little extra muscle behind his defense.

“I put in the work, so can’t just come out and not do what I’ve worked on all year, all summer,” Shayok said. “When the opportunity comes, I’ve just got to stay confident and shoot my shots.”

ava.wallace@washpost.com