Ashley Carew missed a first-half penalty for Cambridge as they were held to a goalless draw by Ebbsfleet.
The U's almost took a sixth-minute lead when Luke Berry volleyed inches wide.
Their big chance came when Paul Lorraine brought down Berry 12 minutes later, but Preston Edwards kept out Carew's spot-kick.
The Fleet could have picked up the points themselves but U's keeper Danny Naisbitt pulled off an excellent save to deny Ricky Shakes.
VIEWS FROM THE DRESSING ROOM
Ebbsfleet boss Liam Daish told BBC Radio Kent:
"I thought second half we finished stronger but we didn't start well.
"It was played in a good spirit. Both teams competed well. They're two young, honest sides that worked as hard as they could.
"We've had three tough games and we haven't been beaten. It starts a bit of a run and we must make sure that we take that into Saturday's game and work harder than the team we're playing against."
Cambridge United manager Jez George told BBC Radio Cambridgeshire:
"I thought the first-half performance was excellent. The goalkeeper's made three or four great saves and saved the penalty.
"They came back into it a little bit more in the second half but we've had enough chances even in the last 10 minutes to win the game.
"We're sitting in the dressing room scratching our heads that earlier in the season we had the run of the ball in one or two games and we're doing twice as much in creating chances and not getting that elusive win."