The Cavaliers (6-2, 2-0 Atlantic Coast Conference) trailed 39-34 at halftime after the Demon Deacons shot 63% in the first half, but Virginia clamped down on defense in the second half and used the fast start offensively to pull away.
"Our defense stepped up," said Hauser, a transfer from Marquette. "Our defense in the first half, it seemed like we were a step behind."
Hauser also grabbed 11 rebounds, drawing praise from coach Tony Bennett. The Cavaliers were outrebounded 16-8 in the first half, but finished even with the Demon Deacons in rebounding at 26 apiece.
"He knows how to pursue the ball and he's sturdy and he finds it and goes after it," Bennett said. "Rebounding is about heart and it's about finding it, pursuing it and going and grabbing it and making it yours, and Sam does that and we need that from more guys."
Trey Murphy III scored 13 points for the Cavaliers, who had all five starters score in double figures. Freshman Reece Beekman scored 12 and added five steals. He said the Cavaliers amped up their defensive intensity in recent practices, "and I definitely could tell during the game."
Isaiah Mucius and Jonah Antonio scored 14 points each and Ismael Massoud had 13 for the Demon Deacons (3-2, 0-2). Wake Forest was 8 for 21 (38%) from the field after halftime.
"You've got to play two halves to win a game, especially against a team like Virginia," first-year Demon Deacons coach Steve Forbes said. "We played about as well as we can in the first half."
Wake Forest used a 19-9 run to open a 24-14 lead midway through the first half. Virginia's 16-6 burst got the Cavaliers within 32-30, but they trailed 39-34 at the half.
Wake Forest: The Cavaliers' trademark tough defense isn't as sharp so far this season, and the Demon Deacons showed that by making their first four 3-point tries and five of their first six. They started 12 for 17 from the field before finishing 23 of 45 overall (51%) and 10 of 19 from beyond the arc (52.6%).
Virginia: The Cavaliers, coming out of their second COVID-19-related pause, were without reserves Casey Morsell and Austin Katstra and three assistant coaches — Jason Williford, Orlando Vandross and Brad Soderberg — because of contact tracing. Bennett also announced that junior guard Kody Stattmann is sidelined with a cardiac condition that he said was unrelated to COVID-19.
"We responded well to adversity and being short-handed," Bennett said, "and, you know, very good second half from my standpoint."
The Demon Deacons remains on the road, playing at No. 21 Duke on Saturday.
The Cavaliers head north to play at Boston College on Saturday.