Captain Paul Wanless headed the visitors in front on 22 minutes after Mark Ormerod failed to deal with a Neil Mustoe free-kick.
Jamie Campbell doubled the Seagulls' deficit on 56 minutes and Neil MacKenzie smashed in Cambridge's third 17 minutes later.
Gary Hart ended an Albion goal famine spanning 561 minutes with a consolation tenth of the season two minutes from the finish.
Jeff Wood's men have now taken one point from the last 30 ahead of Saturday's trip to play-off chasing Plymouth Argyle.
Wood made four changes to the team beaten meekly at Mansfield on Saturday.
Arnott and Doherty were ruled out by calf and leg injuries respectively, while Storer and Sturgess were dropped.
Armstrong would have played, but a shoulder injury ruled him out.
Wood turned instead to Smith and Mayo and King was back after a thigh strain.
Moralee was chosen to partner Hart upfront, his first appearance under Wood.
The former Millwall man's future looked bleak when he was sent off within a minute of coming on as a substitute at Scunthorpe.
That indiscretion earned him an automatic three-match ban plus a fine from the manager.
All of the early action was condensed inside the Albion half as Cambridge passed the ball around with the confidence of a team heading for promotion.
Wanless, who played most of the match as an emergency goalkeeper when Albion won at the Abbey Stadium in October, blazed a couple of shots high and wide from outside the area.
The only threat from the Seagulls came when Minton glanced a header wide from Mayo's 20th-minute cross.
The visitors went in front two minutes later when Ormerod misjudged a free-kick by Mustoe from wide on the right flank.
It sailed over the Albion keeper's head as he tried to cut it out and WWANLESS nodded home at the far post.
Minton used his strength inside the area after some untidy Cambridge defending but the left-foot shot by the little midfield general flashed across the face of the goal.
Hart, who has been carrying a foot injury in recent matches, showed glimpses of the form he has displayed during a promising first season in the pro game.
The young striker's tenacity took him past Eustace before his cross was cleared, then his backward header from a King free-kick was blocked away.
Albion's deficit almost doubled on 38 minutes when Minton's pass was intercepted. Walker, replacing the rested Taylor in the Cambridge attack, advanced before firing an angled drive narrowly wide.
Ormerod gave the crowd palpitations when he was closed down by Walker, but he cheekily outwitted the striker on loan from Aston Villa before clearing.
Although Cambridge looked comfortable Albion were performing a bit better than of late in a half short on goalmouth incident.
Once again, however, they had paid dearly for an individual mistake, with Ormerod the culprit this time.
Albion started the second half in a more positive manner as they tried to end their amazing goal drought.
Inside the opening minute Hart's shot on the turn forced Marshall into his first save of the match, even though it was a routine one.
Minton's effort a couple of minutes later from Hart's lay-off was deflected for Albion's first corner of the contest. It was taken by Minton and headed wide by Moralee, lurking at the near post.
Cambridge stepped up a gear to extend their lead 11 minutes into the restart.
Brilliant work by Benjamin, the visitors' powerhouse forward, set up Campbell, who clipped the ball over the advancing Ormerod from an acute angle.
Minton showed his frustration a minute later when he was booked for clattering into Butler just inside the centre circle.
MacKenzie, making his full away debut on loan from Stoke, blasted home Cambridge's third with 17 minutes remaining following more good work by the bustling Benjamin.
Fans in the main stand responded with chants of "Wood out".
The dispirited Seagulls brought on Barker for Culverhouse on 81 minutes.
Ormerod prevented Cambridge from going even further in front two minutes later. The keeper made a fine reflex deflection at the expense of a corner when Walker met Campbell's centre with a header from point blank range.
HHART grabbed a consolation for Albion two minutes from time, shrugging off his marker to score with an angled right-foot drive across Marshall.
Converted for the new archive on 30 June 2000. Some images and formatting may have been lost in the conversion.
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