Ben Cowles' eighth-inning RBI put the Terps in front for good.
Maura Verleg buried the winner in the 3rd quarter.
Both goalkeepers pulled off a handful of impressive saves throughout Wednesday's match.
The Terps and Hawkeyes have met many times over the years, perhaps no time more dramatic than their NCAA tournament clash in 1999.
Jason Savacool and Connor Staine are among the starters set to take the mound over the weekend.
“Big Ten lacrosse is big guy lacrosse."
"I just kind of want to end it on a good note and leave it all out there."
Tolson has kept the winless Terps in multiple games this season.
It will be the first time coach Mark Montgomery will play a game in the state of Maryland.
Audrey Barber's 9.90 performance on beam secured the victory for the Terps.