An Andy Bond header gave the U's all three points at Walsall.
After conceding late equalisers in three games this season, it was great for the U's to get a late winner themselves, with Bond's header coming in the eighty first minute.
It wasn't a classic encounter but the U's fought tooth and nail for the ball and got their reward following a Brian Wilson cross from the right and Bond's clinical header.
It was an unchanged side for the U's but there was good news in terms of Paul Reid, Ben Williams and Ben Coker all training ahead of the game and being fit for next week's reserve match..
The U's were looking for their second consecutive away win in the league but it was the hosts who had the best of the opening chances, with Mark Cousins the busier keeper.
He had to be on his toes in the seventh minute from a low Matt Richards free kick but held it well with Walsall players looking for the rebound.
Five minutes later, the U's stopper was sharply down to deflect a Jon Macken effort wide of the post and Smith should have done better with his header from the resultant corner.
The U's first effort at goal came almost halfway through the first period, with Henderson heading straight at keeper Brain from a cross by Pat Baldwin.
Kem Izzet was then on hand to receive a lay back from David Mooney but the skipper's shot didn't trouble Brain and went high and wide for a goal kick.
A move involving Richards, Macken and Paterson caused problems and from Paterson's low cross, Andy Bond positioned himself well to clear before a Walsall forward could capitalise.
Macken then shot well wide before the play switched and Mooney, too wide to shoot, was tackled just as he looked to put a cross into the danger area.
The U's midfield had found it hard to get forward as much as they would have liked but two minutes before the break, Bond almost got on the end of a Wilson cross but it just evaded him.
It wasn't a classic first half and the U's would have been a little disappointed that they hadn't managed to create as many chances as they had in previous games.
Once again, the U's defence had dealt with the opposition relatively comfortably but might still have been reminded to stay vigilant to the danger that Reid and Macken could cause.
And it was the home team who started the second half the better but it was a short lived start, with the U's creating the first effort, with Brian Wilson's shot blocked on fifty minutes.
Bond then had a cross cleared after good play by David Mooney to get the ball to Bond, who had found himself in space on the right.
While the football being played wasn't as fluent as in recent matches, the U's were getting a sight of the home goal.
After Perkins was fouled on the edge of the box, Wordsworth's free kick couldn't clear the ball and it wouldn't fall for the U's midfielder to get a shot away.
In the sixty third minute, the U's came close to opening the scoring through captain Kem Izzet.
Once again, the good work was done on the right, with Wilson providing an incisive pass inside. Izzet controlled well and hit a right foot shot narrowly over, with Brain scrambling and relieved to see it clear his crossbar.
On seventy minutes, substitute Kayode Odejayi tried his luck with an early lob but failed to get the elevation needed and the grateful Brain caught it comfortably.
At the other end, Cousins was keeping his concentration despite being a spectator for most of the half and had to be sharply to save from Byfield, following Lescott's left wing cross.
On seventy six minutes, Wordsworth made a strong run through the middle and found Odejayi, who controlled it instantly and was in on the angle.
A slightly mishit shot beat the keeper but just evaded the sliding figure of Mooney and rolled just wide of the target.
Substitute Byfield, who scored a late winner in the corresponding fixture last season,was causing problems and hit the post with ten minutes remaining.
A ball was played into the U's right channel and after getting the better of Wilson, Byfield had the ball at his feet. From a tight angle, he went for the near post but the ball crashed off the woodwork and out for a goal kick.
Walsall were made to pay, with Andy Bond scoring the only goal a minute later.
A great ball down the right found the marauding Wilson and a superb cross found Bond on the far post, the header perfectly placed to beat Brain and a despairing effort by the defender to clear off the line.
It could, and maybe should, have been 2-0 a few minutes later when Wordsworth crossed low and John White couldn't find a finishing touch for what would have been his first ever senior goal.
On eighty seven minutes, the home side should have equalised, with Byfield almost doing the damage for the second season running.
Kem Izzet's pass missed its intended target and Byfield was through on goal with only Cousins to beat.
The U's keeper did well to push Byfield wide but a goal was still expected, fortunately, the shot went over the bar and into the disappointed Walsall fans behind the goal.
There were no further scares, even in the five minutes of injury time, and the three points sent the U's up four places into fifth in the League One table.
It wasn't the best performance of the season but one that showed grit and determination to get the job done.
U's: Cousins, Wilson, Okuonghae, Baldwin, Tierney, Izzet, Bond, Perkins, Henderson (Odejayi 61), Wordsworth, Mooney (White 84).
Subs: Pentney, Heath, Beevers, Vincent, James.