Doncaster substitute Harry Forrester's superb 84th-minute strike deservedly settled a one-sided South Yorkshire derby clash in his side's favour.Rovers looked as if they may have to settle for a point after completely dominating against a poor Barnsley outfit until Forrester popped up six minutes from time.He robbed Barnsley defender Mason Holgate of possession near the corner flag before unleashing a stunning shot that curled into the far top corner.To add to Holgate's and Barnsley's misery the teenage full-back was sent off in the last minute for a rash tackle on Nathan Tyson.But the visitors could have no complaints about the result after looking second best throughout, with goalkeeper Stephen Bywater having only one shot to save from Dale Jennings.Rovers should have won by more goals but failed to convert their superiority in pressure and possession through a mixture of solid defending and shoddy finishing.Curtis Main twice fired way off the mark when well placed, but James Coppinger was unlucky to see a well-placed effort saved by visiting goalkeeper Ross Turnbull's legs.