This was a typically hard-fought encounter between two sides who have drawn six of their last seven meetings and who fought their way to another goalless draw at the end of last season.
Defences dominated after an early shaky spell by Lincoln's back four and there were no more than a handful of scoring chances for the two forward lines put together in the 90 minutes.
Both sides could only really look back to one very good chance each and they came in the first quarter of an uncompromising clash.
A clever pass from Dan Chillingworth sent Dave Kitson into the box in the tenth minute, but with a posse of higher division scouts watching him, the striker shot tamely at goalkeeper Alan Marriott.
Ten minutes later Lincoln looked certain to take the lead when one of Mark Bailey's huge long throws found Gary Fletcher at the far post. He rammed in a header from no more than four yards, but goalkeeper Shaun Marshall made a brilliant reflex save.
It was a physical battle littered with fouls throughout the second half which produced only one moment of excitement for the Abbey Stadium fans.
Ex-Lincoln midfielder Justin Walker raced through the middle threatening to score in the 50th minute until he was hacked down by Simon Weaver, who was booked for the foul two yards outside the box.
Cambridge manager John Taylor admitted: "We ran out of steam a bit after a very good start when we should have scored and got sucked into playing Lincoln's more direct game which didn't suit us.
"That's three games without a goal and although generally we are playing quite well it is a problem we have to sort out." Lincoln boss Keith Alexander commented, "It was a good point to follow our win over York and I thought we had the better chances. With a bit more patience up front I think we could have won it.
"But we are settling into our game now after a bit of an unlucky start to the season and looking more like the side who got to the play-offs last time."