Stan Brown had 11 points and six rebounds to lead Lamar.
Virginia shot 43.4 percent (22 of 53) and held Lamar to 32.6 percent (15 of 46). The Cavaliers turned 14 Lamar turnovers into 31 points.
Virginia (3-2) exploded out of the gate against the winless Cardinals (0-4).
Jesperson, a sophomore who made just five 3-pointers last season, hit three from behind the arc in the game's first 6:34 to propel Virginia to a 16-6 lead.
Lamar, which came into the game averaging 24 turnovers, committed five within the first eight minutes.
A Harris basket, off a pretty feed from Darion Atkins following a backdoor cut, gave Virginia a 30-11 lead. The 19-point spread was the Cavaliers' largest of the half. Virginia took a 32-18 lead into the break.
In the second half, the Cavaliers picked up where they left off. Akil Mitchell had six points of his 10 points during a 14-2 run. The spurt was capped by a pretty play by Justin Anderson. The freshman stole the ball, made a quick pass to Teven Jones, then slammed home a return lob to the delight of the small but boisterous home crowd.