The Saints, who were promoted via the Conference South play-offs last season and won their opening day fixture 3-1 at Kidderminster, are still unbeaten this season after surviving a late onslaught to grab a 0-0 draw in an entertaining game which saw both sides finish with ten men.
Around 500 Cambridge fans made the trop to St Albans and there was an electric atmosphere inside the Clarence Road ground for the first ever Conference game to be staged there.
The game got off to a blistering start with both sides outlining their attacking intentions straight away.
The away side had the first opportunity, Robbie Simpson latching on to a long ball over the top after just two minutes and smashing in a right-foot shot.
St Albans keeper Paul Bastock did well to turn the effort around the post and from the resulting corner the U's Courtney Pitt had a shot deflected wide.
St Albans created their opportunity two minutes later. Ram Marwa lofted a high ball into the box which centre-back Dave Theobald attacked superbly, only to see his header clip the top of the bar. But the effort would not have counted as the referee pulled back play for an earlier foul.
Saints however almost took the lead on ten minutes when Lee Clarke connected superbly with Adam Wilde's corner and his effort looked to be drifting into the far corner but cannoned off the bar.
It was end to end stuff and Cambridge almost took the lead on 16 minutes when Ritchie Hanlon fired in a low free-kick from the edge of the box, but Bastock was equal to it.
It was a frantic opening 20 minutes and tackles were flying in from both sides. The first booking came just before the half-hour. City defender Gary Elphick, who was sent off against Kidderminster on the opening day, was the man shown the yellow card from a crude challenge from behind.
After the frantic start both sides spent the remainder of the half catching their breath but City should have taken the lead just before half-time when Matt Hann latched onto a crossfield ball from Aam Wilde and burst into the box.
He slipped the ball across the face of goal but the onrushing Clarke failed to connect.
Two minutes after the break both sides were reduced to ten men. Elphick, who was booked in the first half dived into a needless tackle on Danny Carey-Bertram on the halfway line and took an early bath for the second time in just four days.
But the U's lost their advantage straight away when Carey-Bertram took exception to the tackle and retaliated by pushing Elphick to the floor. Both managers were left fuming at the stupidity of their players as they trudged off towards the tunnel.
The game descended into a scrappy affair after the double sending off as both sides made readjustments to their formation.
Pitt, who has Championship experience with Portsmouth and Coventry, was unlucky when he turned brilliantly, but could only send a fizzing shot wide of the post.
As the game wore on St Albans were forced to retreat further and further into their own half. Cambridge created several openings with centre-forward Simpson unlucky with a header which just went over.
It was backs to the wall stuff for St Albans in the closing minutes, but the home defence held firm.