Hemsworth’s Neal May had an apparent rush of blood as he flew out of his penalty area and failed to keep possession, with Alex Hallam finishing skilfully from wide.
The only goal of the Welfare Ground game came in the 55th minute, after Doran Jordan sent the ball down the right for his teammate to chase.
It was Emley’s first win in nine games, seven of them in the league, and lifted them to 10th in the table.
Darren Hepworth’s side started well and should have gone ahead after 10 minutes when Jordan was sent through on goal by Liam Schofield.
The attacking midfielder was left with only May to beat, but could only manage to hit the side-netting.
With the win making life difficult, nether side were able to create clear opportunities, although it was Emley who looked the most likely to break the deadlock.
It took a touch of composure from Hallam to do the trick, as first he nicked the ball off keeper May, then netted left footed from the touchline.
The game fizzled out as the hosts restricted Hemsworth to tame efforts from range, much to the frustration of the visiting bench.
Referee David Heap was forced to send Hemsworth manager Wayne Benn to the stand because of continuous dissent.
There was one scare as Emley keeper Adam Lawlor failed to hold a high ball, but he recovered well to smother.