Harry Anderson scored the only goal of the game after 38 seconds, collecting a short back pass from Fraser Horsfall and firing home from a tight angle.
Town battled hard to get back into the game, and went on to hit the woodwork twice, but couldn't find an equaliser.
Here are our player ratings from Sixfields.
1. Liam Roberts
Beaten by a neat Harry Anderson finish after just 38 seconds, Roberts was barely called into action for the rest of the game, aside from two regulation stops from long range efforts late on... 6 Photo: Pete Norton
2. Aaron McGowan
The right-back was very strong defensively, keeping highly-rated Newcastle United loanee Elliot Anderson very quiet. Solid game... 6 Photo: Pete Norton
3. Fraser Horsfall
Horsfall has been fantastic all season, but had a day to forget. It was his woeful back pass that gifted Rovers their goal, and his distribution was poor throughout. Defended okay otherwise though... 5 Photo: Pete Norton
4. Jon Guthrie
Played his part in keeping Rovers' attackers quiet for the majority of the game. Also hit the cross bar with a towering header, but will know he probably should have scored... 6 Photo: Pete Norton