Tranmere goalkeeper Peter Gulacsi scored an own goal 13 minutes from time to hand Hartlepool a 1-0 victory at Prenton Park.
The stopped tried to punch clear a Leon McSweeney corner only to direct the ball into his own net.
Tranmere's Ian Thomas-Moore drew the first save with a 13th-minute header but moments later Hartlepool should have gone ahead.
Ritchie Humphreys was left clear after a mistake but missed the target from twelve yards.
A weak volley by Gary Liddle was comfortably held by Gulacsi just after the half hour in a goalless opening 45 minutes before Humphreys blasted wide and Antony Sweeney saw a header well held by Gulacsi early in the second period.
Tranmere struggled to break down a competent Hartlepool rearguard and Sam Mantom missed the target after some fine approach work in the 72nd minute.
Gulacsi saved well from James Brown in the 76th minute but a minute later his howler gifted United the points.