Gestede pounced for his second league goal in consecutive games on the stroke of half-time when he headed past Ross Turnbull from six yards.
It earned Blackburn a second league win on the bounce and extended their impressive recent record to just one loss in eight.
It also keeps Doncaster in the bottom three and they have picked up just two points from 27 on the road. They remain without a win at Ewood Park.
Gary Bowyer made one change from the side that gave Manchester City an FA Cup fright last week, recalling Jordan Rhodes, his leading scorer.
Opposite number, Paul Dickov, made seven changes from the side that lost to Stevenage last week, including a debut for former Bolton Wanderers and West Brom defender Abdoulaye Meite.
Given their FA Cup performance, it was no surprise to see Bowyer's men fly out of the traps.
They went close twice in the first 10 minutes. First, Gestede showed tremendous hold-up play before laying the ball back to Tom Cairney who skewed his shot wide. Cairney should then have put Blackburn moments later but he blazed over from 12 yards with the goal at his mercy.
Doncaster came into the match in wretched form, having lost six of their last seven in all competitions and the first sniff of a chance came after 28 minutes when Harry Forrester found space on the edge of the area but could only drag his shot wide.
They would have been behind eight minutes before the break but for a wonderful Turnbull save, with the keeper flying to his left to tip behind a swerving Ben Marshall shot.
Blackburn got the goal their dominance warranted on the stroke of half-time, though, Doncaster will be disappointed with their effort.
A long ball was completely missed by Bongani Khumalo, which allowed Rhodes to stand up a cross for Gestede to head in from close range.
The clear chances continued to fall to the home side and Rhodes could have put the game out of sight on the hour-mark but his fierce effort was repelled by Turnbull.
Paul Robinson was making his first league start for 13 months and had to be alert a minute later to tip a dangerous James Coppinger cross behind.
Bowyer described the game in the match programme as Blackburn's biggest so far this season and Robinson secured the win with two magnificent injury-time saves, palming behind an Alex Peterson header, and then producing a superb low save from a Richie Wellens volley.