It was Palace's third win in four games, all of them at Selhurst Park.
Doncaster, who are now without a win in four league matches, started well, with James Hayter missing two good opportunities, but Palace took the lead through Counago's second of the season 10 minutes before the break.
There were chances at both ends in the second half with Wilfried Zaha hitting the post for Palace but home goalkeeper Julian Speroni also saved well from Brian Stock and John Oster.
Source: PA
