A Brandon Kavanagh strike midway through the second half helped Shamrock Rovers to a 1-0 win at Eamonn Deacy Park.
The friendly proved to be a worthwhile exercise for both sides and Alan Murphy will have been pleased with the performance of side, considering he was missing over 10 players.
Stephen Bradley fielded a strong starting eleven but it was United who threatened first when Dean O’Halloran flashed a shot narrowly wide of Leon Pohls’ post.
Kevin Horgan had to be alert to push the ball over the crossbar from an angled header from Liam Scales.
Thomas Oluwa had two big chances to open the scoring for the Hoops, but the young striker spurned both.
The opener arrived when Brandon Kavanagh pounced on a rebound from a free-kick, the midfielder drilled a shot goalwards that took a deflection, wrong-footing Kevin Horgan in nets.
United went close to finding a leveller late on when Donal Higgins rattled the crossbar.
Galway United: Horgan; Lynch, Smith, Murphy, Horgan (Ubaezuonu); Warde (Collins), Duggan (Waweru); Higgins, Molloy (Sacramento), Christopher (Farrell); O’Halloran (O’Dea)
Shamrock Rovers: Pohls (Clarke), O’Brien, Lopes, Scales, Lafferty, Bolger, Finn, McEneff, Kavanagh, Oluwa, Williams
Referee: Marc Lynch