The visitors went close minutes later after Jose Baxter's attempts to shield the ball out of play were interrupted by a fast-approaching Mark Cullen, with the ball eventually falling for a corner
Conor Sammon had the best chance of the half with his shot from six yards deflecting off Tom Aldred
The Blades drew first blood on the hour when Jay McEveley drove his corner into the path of a waiting Sharp, who struck low and hard from inside the box
It was 2-0 within 12 minutes after Sharp threaded the ball through to substitute McNulty, who rifled home from the edge of the area
United could not find a third but comfortably secured all three points to leave relegated Blackpool still without a win this season
Source : PA
Source: PA