The U's have been beaten at Crewe, after the home side staged a second half comeback to seal all three points.
It was looking good for the U’s at half time, as an early Freddie Sears goal and a great Ian Henderson lob had put the U’s two ahead.
That all changed in the second period though, as goals from Dalla Valle, Murphy and Pogba gave the hosts the win.
Dunne made two changes to his starting line-up, bringing in new loanee John Sullivan in goal and Freddie Sears in attack.
Mark Cousins and Gavin Massey stepped down to the bench, and they were joined by Josh Thompson, who along with Sullivan, had joined on loan from Portsmouth on Friday.
Crewe boss Steve Davis made only one change to the team that beat Doncaster in the week, bringing in Robertson for Mellor.
The U’s came into the game having lost their last two fixtures and looked determined to make amends.
And they got off to the best of starts, scoring with their first real foray forward with less than three minutes on the clock.
Ian Henderson picked the ball up on the right, played a one-two with Jabo Ibehre and made his way to the by-line.
His low cross into the near post area was met perfectly by Freddie Sears, who sidefooted firmly into the bottom corner.
The home side looked for a quick leveller, but Aneke’s shot a minute later cleared the bar.
Another cross for the U’s gave the home side something to think about, with Bean making a run from midfield but headed straight at Martin.
After that early action, the game settled into a bit of a lull, with the home crowd frustrated with their team’s inability to break through the U’s defence.
That frustration grew on twenty eight minutes, when the U’s scored with a fantastic finish from Ian Henderson.
A long ball over the top from Magnus Okuonghae needed a great first touch from Henderson – that came and his second was even better as he lobbed Martin to make it 2-0.
The U’s loan debutant John Sullivan had little to do apart from organise his defence in the opening half hour and he had to wait until the thirty eighth minute for his first meaningful action – saving comfortably from a long range effort.
He had to be sharper four minutes later, as he acrobatically turned away a Dalla Valle effort after the Crewe forward had got in front of Eastman to divert a low cross goalwards.
The final effort of the half came from an Anthony Wordsworth free kick, which went narrowly wide with Martin scrambling across his goal.
Dunne would have been happy with the response of his players in the first half, following two successive defeats, but may have been warning them about Shrewsbury, where a two goal lead was surrendered a couple of weeks ago.
As in the first half, the U’s were on the front foot at the start, with Wilson not getting a good contact on his volley from the edge of the area on forty seven minutes.
Unfortunately, Crewe got a goal back two minutes later, with the U’s back line asking for an offside flag as Pogba and Dalla Valle broke clear.
As Sullivan closed down Pogba, he calmly passed it across to Dalla Valle who had the simple task of putting the ball into the empty net.
Michael Rose was furious with the decision by the officials and went into the book for his protestations.
Sullivan then had to react quickly as a shot came at him quickly, with teammate Okuonghae blocking his view.
Just after the hour, action at both ends saw Sears and Bean denied at one end and then Okuonghae penalised for a handball in the U’s area.
Crewe skipper Luke Murphy stepped up and put the spot kick into the bottom corner to bring his side level at 2-2.
A wide free kick than found its way to Dalla Valle but the forward’s left foot effort only found the side netting.
Aneka headed off target before shooting narrowly wide and the home side could sense a winner.
Dunne put on Clinton Morrison for Craig Eastmond on seventy one minutes but three minutes later, Crewe did get a third.
Moore did well on the left wing and his far post cross found Pogba unmarked to head home and put Crewe in the lead for the first time.
Anthony Wordsworth tried his luck from distance but the shot went straight as Martin.
That was the U’s skipper’s last involvement, as he and Sears were replaced by Gavin Massey and Andy Bond.
On eighty two minutes, Bean got forward from midfield but his shot from the edge of the area flew over the crossbar.
The U's had the majority of the possession in the closing minutes but couldn't find a way through.
A last minute strike from Massey went over the bar, seconds after Bean's effort was blocked by Morrison.
The home side saw out the injury time and the whistle went to huge applause in Cheshire for the home side's comeback.