Jack Stretton’s second-half goal enhanced Stockport’s promotion hopes with a 1-0 victory at Sutton.
It was a defeat which dealt a blow to the hosts’ play-off ambitions and, to make matters worse, they lost captain Craig Eastmond after just six minutes.
Sutton goalkeeper Jack Rose produced a good first-half save after Stretton was slipped through.
David Ajiboye was the hosts’ best outlet, his 20-yard strike going over as the Hatters dominated the first half.
Kyle Wootton blasted a great chance over the bar early in the second half for the visitors.
Their dominance eventually told in the 52nd minute as the hosts failed to clear Ryan Rydel’s cross before Stretton poked home at the far post.
Ben Hinchliffe produced two fine saves to stop Sutton scoring an instant equaliser.
First he turned Will Randall’s strike behind before he kept out Joe Kizzi’s header from the resulting corner, with Coby Rowe’s follow-up effort cleared off the line.
County came close to a second when Rydel’s free-kick hit the post before Hinchliffe kept out substitute Enzio Boldewijn’s 20-yard effort.