Cambridge produced a resolute display to hold League One leaders Portsmouth to a goalless draw.
The U’s started brightly, with Sullay Kaikai’s cross needing to be tipped over by Will Norris before a Kaikai cross was scuffed wide by Danny Andrew.
The biggest chance of the first half came on 31 minutes when Abu Kamara’s overhit cross for the visitors smacked back off the far post, with Colby Bishop’s rebound kept out by a superb Ryan Bennett block.
Pompey were denied again before the break when Conor Shaughnessy’s effort was deflected off target following a scramble from a corner.
Portsmouth continued to press in the second half, with Zak Swanson firing straight at Jack Stevens before Paddy Lane shooting over from outside the box just after the hour.
The U’s almost snatched an opener themselves 18 minutes from the end after great work by substitute Saikou Janneh but Jack Lankester’s close-range shot was too close to Norris.
The leaders nearly grabbed a winner deep into added time only for Stevens to deny Bishop.
