Forest Green boss Robbie Savage was furious after striker Ricardo Rees was sent off during the 1-1 draw at Sutton.
Rovers went ahead after 21 minutes when Rees was fouled in the area and Kyle McAllister tucked away the penalty.
But shortly before half-time Rees had the ball in the net again, only to be penalised for handball and shown a second yellow card.
Savage was booked for his protests and the 10 men were denied a victory when Sutton’s Jayden Harris squeezed the ball home a minute from full-time.