Ibehre volleyed just wide from the edge of the area for Colchester before the former MK Dons striker broke the deadlock with 12 minutes to go when he slotted in from the edge of the area, after Freddie Sears had closed down goalkeeper Ian McLoughlin's clearance.
And Sears wrapped up the U's win in the final minute when he tapped in from close range, following fellow substitute George Porter's low cross.
Sam Mantom's saw his strike deflected inches wide for Walsall in the first half, while James Baxendale wastefully shot across the face of goal and wide, after he was picked out by Mantom following a swift counter attack.
The closest Colchester came to scoring before half-time was when Ibehre's brave header looked goalbound before being cleared, following John White's long punt forward.
The game continued in similar tight fashion in the second half, although the U's looked the more likely to create chances.