Eatherton's win came in a third set super-break, 6-1, 4-6, 10-7.
The Gusties, who remain undefeated in MIAC play this year, won the other five singles matches by identical 6-1, 6-0 scores.
Kelly Gust (Sr., East Grand Forks, Minn.) and Liz Gunderson (Sr., New Prague, Minn.) played to a 3-8 loss at first doubles.
The Pipers drop to 2-13, 1-7 MIAC with the loss. They will next host their alumni tournament this Saturday, April 25, at 10:00 a.m. They then travel to Saint Mary's for a 12:00 p.m. match on Sunday, April 26.