Maddy Murphy's fourth-quarter tally prevented the Terps from upsetting the Hawkeyes.
"For us, it’s about focusing on Maryland," coach Missy Meharg said.
The Terps will meet former conference rivals in Duke and Boston College over the weekend.
"If you can't battle with each other off the field, then there's no way you're going to do it for each other on the field."
The Terps held two exhibition matches over the weekend, playing their annual Red-White scrimmage and hosting local club team, DC Dragons.
Tornetta was announced as a transfer for the Terps on May 28.
Tornetta spent her first three seasons with Princeton where she appeared in back-to-back Final Fours.
The Terps did not register a shot on goal.
The Terps tallied 13 shots but were shutout Sunday.
Wolverines goalkeeper Anna Spieker made five saves.