The visitors had got off to a flying start this season - and sat second in the 'as it stands' table when in the lead in this match - but the U's kept probing to ensure that they grabbed a point by the final whistle.
At times, the U's looked tentative but as the game wore on, they loosened their shackles to push on more around the opposition goal.
They fell behind to a controversial goal as Kyle McFadzean handled to dispossess Mark Cousins before tucking home, but the U's remained focussed on their task.
And although it looked like time might run out for them, but Anthony Wordsworth's fiercely taken penalty ensured they lifted themselves up two places in the league table.
It was a small but strongly supportive crowd that backed the U's, as they made two changes to the side that had lost to Doncaster on Saturday, with Anthony Wordsworth and Clinton Morrison coming in for Andy Bond and Freddie Sears.
It was Morrison who had the first half sight of goal, with his shot from the edge of box scuffed and blocked by the visiting defence.
And Crawley’s back line had to be in the right place at the right time to deny Massey who looked like he might slide home from close range from a Henderson squared ball.
The visitors were forced into an early change as Cooper came off to be replaced by Simpson after just eight minutes.
Crawley’s first chance came ten minutes later, as they got in down the left and sent over a cross to the far post.
Weekend goalscorer Alexander was waiting on the far post, but as he slid in, he failed to fully connect with the ball and it was an easy collect for Cousins.
The visitors were beginning to grow into the game, and Ajose poked a shot wide of the post from close range but his blushes were spared as the linesman raised his flag for offside.
Chances remained relatively restricted, but Wordsworth darted forward to get onto a throw early, only to shin his effort well wide of Jones’ goal.
The U’s were doing their best to get their game going and a swift counter attack down the left saw Massey get to the byline, but his low cross lacked the fizz to trouble Jones.
A long range shot by Sadler at the other end did have the necessary power on it, but lacked the direction to get on target as the ball whizzed past the near post.
The first half finished goalless and without too many chances, but the U’s would at least take some heart from the fact that they’d been solid in keeping the visitors restricted to long range efforts.
The visitors started the second half brightly and had a shot that hit the outside of the side netting, as Jones went close.
Backed by a vocal home crowd, the U’s grew into the half and Henderson stretched Jones with a header that was heading for the top corner, before Morrison ran out of space at the byline as his shot was easy for the visiting keeper to hold.
The visitors went close with fifteen gone in the second half, as Ajose’s cut back was met by Alexander and Okuonghae got in the way to deflect behind for a corner.
At the other end, a patient U’s build up saw Wilson whip over a cross that Wordsworth got up to but, under pressure, Wordsworth couldn’t connect fully with the header.
It was a more open second half, with the U’s starting to find their gear.
Jones almost killed off the U’s enthusiasm with a shot that cracked off the outside of the post, before the home side made their first change with the introduction of Sears for Henderson in a straight swap.
The visitors then hit the woodwork for the second time as Adams’ shot was tipped onto the woodwork by Cousins and for a corner.
Then the Reds scored in controversial circumstances as it seemed that McFadzean headed the ball out of Cousins’ hands only for the officials to give the goal.
The U’s made a second change with 15 minutes remaining, with O’Toole coming on for Izzet to give the home side another pair of fresh legs.
Chances remained limited for the home side though, with Sears volleying an effort wide of goal.
The U’s drew level with five minutes to go though, as Bean was brought down in the box chasing a loose ball and Wordsworth got enough power on his penalty to bury it past Jones.
Straight afterwards though, the U’s nearly went behind as another shot crashed against the post with Cousins stretching.
There were five minutes of additional time for the two sides to find a winner but, after a livelier second half, neither side could find the crucial goal to grab all three points.