Jimmy Six started the game for Ashford and allowed three runs (two earned) on 11 hits in 5 2/3 innings, walking two and striking out four.
It was Ashford's turn to rally for the win in the second game.
St. Ambrose wasted no time jumping on Ashford starter Pat Macaione, scoring two times in the first and once more in the second, knocking Macaione from the game. The Ashford bullpen silenced the Bees' bats the rest of the way, yielding one hit over the final five innings.
The AU offense tied the game at 3-3 in the fifth on an RBI single from Roberts and a two-run double off the bat of Pattison. One inning later, Roberts delivered the game-deciding hit, driving in Courtney with a single up the middle to make it a 4-3 game.
Junior Kevin Delzell (1-1) picked up his first win as a member of the Saints, striking out two hitters in two innings of scoreless relief.
Next up for the Saints is their home opener at noon Thursday against Benedictine University at Springfield (Ill.) at Ashford University Field.