But Lincoln could have won by more but for Rovers keeper Steve Phillips who produced a string of outstanding saves.
When Phillips was beaten he was twice saved by the woodwork as well two goal-line clearances in a game almost totally dominated by the home team.
Rovers were disrupted after just 90 seconds when midfielder Craig Disley collided with team-mate Steve Elliott on the halfway line as both attempted to clear.
Disley suffered a badly cut leg and, after lengthy treatment, limped off to be replaced by Aaron Lescott.
The injury clearly threw Rovers off balance and they struggled to get into the game.
After only 13 minutes Lincoln almost went in front when a corner from Lee Frecklington found the head of Lee Beevers.
The centre-back's effort beat Phillips but Chris Carruthers saved Rovers with a goal-line clearance. Phillips was in action in the 32nd minute when he pushed out a powerful shot from Ryan Amoo.
But four minutes later the Rovers defence was at sixes and sevens after a break and cross from Matt Birley. Frecklington smashed a shot against the post and Mark Stallard followed up only to see his effort blocked at point-blank range by Phillips.
Six minutes later a powerful shot from Stallard was pushed out by Phillips, before Forrester beat the keeper with a follow-up shot only for Elliott to clear off the line.
Seconds later Frecklington fired over a corner which Beevers headed against the bar.
The Rovers defence looked certain to crack but a superb one-handed save by Phillips kept out a powerful shot from Birley.
Lincoln finally edged in front in the third minute of stoppage time at the end of the first half.
The referee ignored a penalty claim when Birley appeared to be fouled but as the game continued Elliott tripped Forrester for the resulting spot-kick. Forrester hit the back of the net sending Phillips the wrong way to bring his tally for the season to 13.
Lincoln continued to dominate the second half and Frecklington almost increased their lead after 62 minutes but Phillips produced another great save to keep out his right-foot shot.