Two early goals were enough for the U's as they picked up another massive three points in their quest for promotion.
They were two up in thirteen minutes, could have had a third before the quarter hour mark and had other chances in the game.
The Seagulls tested the U's to the limit, creating plenty of chances and making Ben Williams pull off some first class stops.
However, the visitors held on for their third away win of the season and ensured they kept up the pressure on the other sides at the top.
The U's made just the one change to their starting eleven, with Kem Izzet coming in for the injured David Fox.
Medy Elito took Izzet's place on the bench, but the U's were otherwise unchanged as they looked to extend their recent good form.
The U's started on the front foot with a series of throws down the right hand side pinning the Seagulls back in and around their penalty area. It was a bright start from the U's, who were lively off the ball as well as on it.
One patient spell of possession ended with the ball being laid out to Ifil and he sent over a superb cross that looked like Platt might get on the end of, but the referee pulled him up for a foul on Tunnicliffe.
The home side didn't get into the U's final third until seven or so minutes into the game as Forster twisted and turned before firing in a low shot from a narrow angle that Williams was more than happy to watch the ball go by the post.
But it was the U's who were looking the more creative, getting into dangerous areas in the Seagulls half, with offside flags denying O'Toole and Lisbie within the first fifteen.
The U's were in front on the ten minute mark. Okuonghae dropped the ball onto the chest of Lisbie and Ifil was the first onto the ball to drill a superb effort past the keeper for his first goal for the club.
Two minutes later and the U's were at it again, as Wordsworth picked up the ball and laid it back to Lisbie, who curled an effort only inches over the bar.
The U's were lively in the early stages, and they doubled their advantage before the quarter of an hour mark arrived.
A fantastic move saw them get the goal. White's throw in saw Lisbie hold the ball up down the right, and he in turn laid it onto Ifil on the overlap.
He still had plenty to do, but cut inside his defender and took his time on the byline to lift in a cross that Wordsworth made no mistake with as he powered home a header past Brezovan for his fourth of the season.
Such was the U's start that El-Abd was replaced within the first twenty minutes by McNulty.
The substitute hadnt even settled into the game as the U's nearly got their third. A corner was not fully cleared by the home side and Lisbie acrobatically crashed the ball against the bar with a overhead kick.
The home side had their first chance on eighteen minutes though as a warning to the U's. Tierney let the ball drop over his shoulder and Bennett was first to it. Williams had come to collect, but it was pushed wide of the exposed goal by the winger.
A minute later and a dangerous cross was swung in from the left by McNulty and Murray stole a march on Reid but, from inside the six yard box, he lifted his effort over the crossbar.
The front man did better from another cross down the left hand side as he tucked home past Williams, but the Seagulls celebrations were shortlived as the linesman's flag quickly went up before the ball had even settled in the net.
26 minutes had gone when the U's went close again. A Tierney throw in was flicked on by Platt and, as it landed at Wordsworth's feet, he lashed an effort just over the crossbar.
The home side were winning a number of free kicks as the half hour mark arrived and Williams pulled off a sensational save from one at that time.
Bennett smacked in a low effort under the U's wall and, as it appeared the other side of the defensive line, Williams got down to ground level and got a superb low hand to the ball to turn it around the foot of the post.
The home side were gaining some momentum at this point, but the U's managed to ride that storm and calm things down again as the half time interval drew ever closer.
They too had a goal disallowed ten minutes before the break as Lisbie tucked home but was given offside as he slotted home a rebound.
Crofts then forewent another good opportunity for the home team. A low cross to the near post saw Williams block Murray's shot and the midfielder could only lift his follow-up effort over the bar.
Then White was in the right place at the right time to head off the line from Elphick's effort from a corner, as the U's worked hard to protect their two goal advantage.
However, the host of chances that the Seagulls had created came to fruition just before half time as another cross came into the area. It flicked off a U's head and Dicker dived low to bury his header past Williams.
Lisbie then forced Brezovan into a save under his bar with a long range effort, but the U's went in at the interval a goal ahead.
The U's started the second half as they did the first, on the front foot and getting into the corners behind the Seagulls full backs.
But the home side got back to where they left off with a number of corners within the first ten minutes of the second period. The U's stood firm, however.
Wordsworth was presented with a free kick on 57 minutes from distance and it flicked just off the wall to go inches wide of the post. From the corner, O'Toole won the header on the second cross, but Brezovan collected.
Ifil then sent in a dangerous cross that just eluded Platt and Lisbie in the middle, but the U's were at least creating chances again.
Platt was replaced on the hour mark, though, with Hackney coming on down the left hand side as the U's went 4-5-1.
It saw the U's starting to protect the wings where Brighton had had some joy, but the home side responded by bringing on Dickinson for Hoyte for the final twenty-five minutes.
And, whilst both sides waited to create another chance, the U's made their final change midway through the second half as they introduced Odejayi for Lisbie.
An acrobatic effort from Crofts was the next to come, but his shot over his shoulder was well over the bar in the end.
Murray looked like he might get in on goal on 68 minutes through Dickinson's ball. Reid got a crucial touch and forced the front man out wide and Williams saved the follow-up effort well.
Hackney earned the wrath of the home fans for a foul on his man by the byline, but the referee didn't give the U's man even a yellow when he easily could have done so.
The match had entered its final twenty minutes with the home side looking more likely to get the next goal, but it was the U's who were next to go close with fifteen minutes remaining.
Odejayi played it to Hackney, who in turn laid it back to O'Toole and he scuffed his shot and into the goalkeeper's arms.
The Seagulls went down the other end and nearly got the equaliser. A clever low cross by Forster was missed by the U's and it fell to Murray eight yards from goal. His shot clipped the post and went away to safety, much to the U's relief.
Cox was introduced for the home team for the final thirteen minutes of the game, but the U's were the ones in the right part of the pitch as the game entered its final ninth.
Williams then pulled off another good save from another good Bennett free kick and, more importantly, the goalkeeper held onto the ball to ensure no further danger arose.
For the second game running, Ifil was replaced to a standing ovation and Gillespie was added for the last six minutes to give the U's fresh legs up front.
Straight away, he blocked a Tunnicliffe clearance to pin the home side back in their own final third. But Forster was still able to go close with five minutes remaining as he peeled off his man, but Williams pulled off another superb stop.
At the other end, Brezovan pulled off a great save from Gillespie as the U's striker made the most of some good hold up play by Odejayi just on the edge of the area.
Just before four minutes of injury time got underway, Forster looked like he might get in round the back, but White forced him inside and the striker could only lift his effort over the bar.
The home side were finishing in the ascendancy, but the U's managed to hold on and move back up to third in the League One table.
U's: Williams, White, Okuonghae, Reid, Tierney, Wordsworth, Izzet, O'Toole, Ifil (Gillespie), Lisbie (Odejayi), Platt (Hackney)
Subs: Cousins, Heath, Batth, Elito