Freddie Sears came the closest to opening the scoring in the first half, but saw his effort from the edge come back off the post.
The home side had the best chances in the second half though, but couldn't beat Sam Walker.
There was a big shout for a penalty to the U's in the second forty five but the referee waved play on, much to the home side's relief.
A point and a clean sheet were positives for the new boss, who tinkered with the line up but didn't make wholesale changes.
In what was his first game in charge, he made one change to the U’s starting eleven, an enforced one with Jabo Ibehre unable to travel through injury.
He was replaced by Sanchez Watt, who had came on and made an instant impact as a second half sub against Peterborough seven days previously.
There were new faces on the bench though, with new signing Byron Lawrence included, along with striker Dominic Smith.
It was a cagey start to the game, with the hosts edging possession and having a marginal advantage in terms of territory but with no chances to test Sam Walker.
The first real chance did fall to the U’s though, with Freddie Sears unlucky not to open the scoring.
Good play on the right saw Gavin Massey and Sean Clohessy combine and the latter passed across the edge of the area into George Moncur.
The West Ham loanee cleverly dummied the ball and Sears saw his first time effort come off the inside of the post, past the other post and out for a goal kick.
Three minutes later, the woodwork of the visitors was hit but Walker was comfortable as he watched the ball clip the back of the top of the bar.
Both sides were guilty of losing possession in the middle of the pitch and Chambers almost capitalised but couldn’t divert Manset’s cross on target.
The U’s were controlling things as the half wore on and were knocking on the door around the half hour mark.
Sears had an effort well blocked after good work by Sanchez Watt, Moncur curled a shot wide and Sammie Szmodics was also thwarted by a last ditch block.
With eight minutes remaining of the half, the hosts almost made the U’s pay for another loss of possession, with Manset shooting narrowly wide after Gilbey was dispossessed.
On the stroke of half time, the home side had a free kick, with Clohessy fouling Manset, but Taylor hit the set piece over the bar.
While it took Humes’ squad a while to get going in his first game in charge, he would have been relatively pleased with the first forty five minutes of his tenure.
The one thing that Humes would have wanted was for his side to start the second half more on the front foot than they had the first.
His request was answered, with the U’s pushing players forward and keeping the home side pegged back.
They didn’t test O’Donnell in the home goal though, despite a couple of early crosses whipping across the six yard box.
Most of the joy was coming down the U’s left, with Watt causing problems for Walsall’s right back Liam Kinsella, son of U’s legend and recently departed assistant boss Mark.
And Watt felt, along with the U’s bench and travelling support, that he should have been awarded a penalty.
He made a strong run from outside to in and then seemed to have been fouled as he went past the centre half just inside the box.
The referee looked like he had the whistle to his mouth but waved play on, much to the former Arsenal man’s annoyance.
A quiet spell followed but there was still an effort on goal for youngster Sammie Szmodics.
Watt did well to regain possession in midfield and was upended as he passed sideways, with the referee playing a good advantage to allow Watt’s ball to find Szmodics.
After making good strides into the Walsall half, Szmodics let fly from twenty five yards but could only find the midriff of O’Donnell.
Dominic Smith came on for his debut, replacing Gavin Massey as Humes made his first substitution as the U’s boss.
He had to make another when Ben Gordon was smacked in the ribs with a vicious cross shot and had to be replaced by David Wright.
The final stages saw the home side create the last couple of chances but the first resulted in Sam Walker’s first save of the game.
George Moncur was harshly adjudged to have fouled on the edge but Walker dived full length to deny the home side a late winner.
That save came in the ninetieth minute but there was still time for the hosts to have another sight of goal.
Bradshaw, who looked the most likely to score for Walsall, got in behind the U’s defence but having taken the ball a bit wide, shot narrowly past Walker’s far post.
The referee blew the final whistle after five minutes of injury time and the U’s had ended a run of five consecutive defeats.
The point and the clean sheet would have been positives for new boss Tony Humes, with the U’s taking on Leyton Orient in a week’s time.