Even though midfielder Malcolm Johnston was sent off in the first half, the Terps managed a 0-0 tie with the Badgers.
Coach Sasho Cirovski switched to a 3-5-2 formation from the Terps' usual 4-3-3.
Defender Brett St. Martin scored in the 109th minute.
The Wildcats capitalized on a bevy of Terps miscues.
The Terps equalized in the second half but couldn't hold on.
“I think we’ve got some really terrific young players who came here to contribute, and they already are.”
Richardson joined the Terps as a right back but has since shifted into Samuels' vacant role.
The Terps battled through a sluggish first half.
The Terps were No. 24 last week.
Di Rosa scored the game-winning goal in the Terps' 1-0 win over Villanova on Monday.