John Prince’s side were unable to build on summer successes over Ohio Wesleyan University and Blackpool Ladies after falling 2-0 behind at the break.
The first goal arrived when Rovers gave the ball away in centre midfield and the American visitors broke quickly to score.
The Missouri-based outfit doubled their lead from a corner, after Rovers’ appeals for handball were waved away.
Rovers responded well after the interval and got back into the contest courtesy of Nichol Forster’s third goal in her last two games.
From then on, the hosts were very much on the front foot, dominating possession in the Panthers’ half, but without managing to get the equalising goal.
“It was a really close game against a very fit, energetic and physical side,” said Prince.
“They challenged us in areas we haven’t been challenged in yet this pre-season, which was a good learning experience for the players.
“It was ideal pre-season preparation, because the best way to describe them is relentless. They constantly put us under pressure and competed for every ball. I enjoyed the game and especially how we played in the second half.
“We now look forward to welcoming Padiham to the Anchor Ground on Thursday, for our first fixture at our new home.”