Cambridge 0-1 Tamworth
Liam McDonald scored the only goal as Tamworth narrowly beat Cambridge.
The Lambs ended a five-game winless away run when McDonald's shot from the edge of the box looped in after getting a deflection from Blaine Hudson.
Tom Shaw had a chance to level it but his long-range drive was saved well by Jonathan Hedge.
And the play-off chasers went even closer late on when striker Michael Gash saw his header come off the visitors' crossbar.