With the Tar Heels looking for a dose of emotion late in the first game, Underwood lifted a touch shot over a Maryland block and complained to the referee when he didn't rule that the ball had hit the ground.
When he made the call in UNC's favor, Underwood pumped her fist and continued to encourage her teammates after the Terrapins called a timeout.
"Even though we had a good crowd, it was a dead day," she said. "We were kind of struggling through the first game, so I decided we needed some energy."
Underwood's kill sparked a 9-1 Tar Heel run that put away the first game and helped power UNC to its second 3-0 sweep of the weekend. The Tar Heels dominated Florida State the previous night to clinch the team's first outright regular season title since 1998 and avenge their only ACC loss of the season.
"I think it's important for just getting momentum and us feeling good about our game going into the ACC tournament," said UNC coach Joe Sagula. "Not feeling like we're just pulling it out, just winning. We're winning well."
UNC (28-2, 15-1 in the ACC), has struggled throughout the year with putting teams away.
But after taking a pair of 30-24 wins to open the match against the Terrapins (18-13, 7-9), UNC maintained the lead and finished the third game 30-19.
The Tar Heels were led by seniors Underwood and Laura Greene, who each had 13 kills and 10 digs. Molly Pyles hit a perfect 1.000 in the second game, setting a UNC single-game record.
The offense was impressive, but the defense created the wins. UNC outblocked Maryland eight to four, holding the Terrapins to a .102 hitting percentage.
