Promotion chasing Plymouth extended their unbeaten League Two run to five matches by ending Cambridge’s four-match winning streak in a 0-0 draw.
Argyle should have been ahead by the break but some superb defending by United denied the high-flying home side.
Substitute Samir Carruthers headed off the line as central defender Niall Canavan’s header looped over Cambridge keeper Callum Burton from Antoni Sarcevic’s corner.
Burton made a superb point-blank save to deny Argyle striker Byron Moore as he looked set to open his account after 28 minutes.
United had penalty appeals waved away by match referee Will Finnie as Canavan tumbled United targetman Paul Mullin just before half time.
Cambridge came closest to scoring in the 68th minute when substitute Reggie Lambe first-timed Idris El Mizouni’s cross inches past the post.
Leon Davies did well to tee up his own volley before firing just wide as United continued to press.
Argyle’s best second half goal effort came late as substitute George Cooper’s 20 yard free-kick shaved past the post.