Daniel Powell's second-half goal sealed three vital points as Northampton claimed a 3-1 victory on the road over fellow League One strugglers AFC Wimbledon.This was the Cobblers' fourth win in six games and it allowed them to move three points clear of the relegation zone and above the Dons, who are now just one point above fourth-bottom Oldham.Northampton were awarded an early penalty when John-Joe O'Toole was judged to have been brought down by Dons goalkeeper George Long, with Matt Grimes slamming his spot-kick into the top corner.The home side drew level just two minutes into the second half when Lyle Taylor's corner found its way to Deji Oshilaja, who headed in at the far post from close range.But Northampton restored their lead just after the hour mark when O'Toole flicked the ball back for Matt Crooks, who finished neatly into the bottom corner.The Cobblers then gave themselves breathing space as excellent move up the pitch ended with O'Toole finding Powell, who passed a precise effort past Long.