Bristol Rovers lost 2-1 at West Country rivals Swindon, early on Saturday afternoon.
Swindon were ahead after four minutes when top scorer grabbed his 29th of the season following a defensive mix-up.
However Rovers equalised when Kevin Amankwaah's clearance rebounded off Darryl Duffy's foot to skid beyond goalkeeper Phil Smith after 21 minutes.
But it was Swindon who took the three points, Cox making it a brace nine minutes from time when he scored from 15 yards out.