Away-DAY specialists Doncaster chalked up another impressive win on the road.
Iain Hume consigned managerless Portsmouth to a sixth straight defeat.
The Canada international took advantage of hesitation between Pompey goalkeeper Mikkel Andersen and skipper Brian Howard to slide the ball home.
Another former Sheffield United player, Lee Williamson, should have equalised for the home side after the hour mark but miscued his effort.
But Rovers hung on to maintain the pressure on the top six of League One.