Masonius tallied her first double-double of the season and tied her season high with 15 points for the Terps. She played 37 minutes and was a team-high plus-34.
The Terps advance to Saturday's Big Ten tournament semifinal, where they'll play the winner of No. 4 seeded Michigan State and No. 5 seeded Nebraska at 2 p.m. EST.
While depth has been an issue for the Terps throughout the year, their role players excelled on Thursday to help the team advance to the conference tournament quarterfinal.
The Terps limited the Nittany Lions after surrendering the second-most points in program history to them earlier in the season to secure a crucial victory.