Peterborough extended their unbeaten away run to four games with a dogged display in a 0-0 draw at Tranmere.
There was never much between these sides and goal chances were few.
Home skipper Graham Allen was unlucky in the 13th minute when his shot saw the ball deflect down off the crossbar before being scrambled away.
Then, in the 25th minute, Ryan Taylor hit the side netting from a header past by Gary Jones.
Leon McKenzie wasted a good couple of chances for Peterborough and then David Farrell just failed to connect with a McKenzie cross in front of a gaping goal.
Simon Haworth did find the net for Tranmere seconds after half time but the goal was ruled out for a marginal offside decision.
The visitors nearly snatched the lead on 54 minutes but a header by Adam Newton was headed away by Allen with the home keeper stranded.
John Achterberg did well to turn away a powerful free kick by Matthew Gill.
The Merseysiders then piled on the pressure in the way of a 20 yard strike by substitute Chris Dagnell in the 88th minute which was well held by Mark Tyler.
Jones headed over from a Gareth Roberts cross in the 90th minute and deep in injury time Haworth missed the target from an Iain Hume cross.
Allen was outstanding for Tranmere, while Simon Rea and Gill were excellent for United.
Tranmere's Tyrone Loran and Peterborough's Neil Wood collected first half cautions.
Peterborough boss Barry Fry said: "We showed a lot of passion in what was always going to be a difficult game for us. I can't ask for more.
"I can't fault the lads for effort. I thought we might snatch a goal in the second half but it was not to be" Tranmere manager Ray Mathias said his side lacked confidence and sparkle.
He added: "We needed a goal but we had two disallowed and another effort kicked off the line.
"But we have not lost the game and have kept a clean sheet so it is not all doom and gloom. Their keeper was a lot busier than ours."