Michael Flynn's men – looking to halt their recent slump in results – made a nightmare start as they gifted the U's the lead.
Hayden White, having appealed for an offside that did not come, let Frank Nouble in on goal and the target man capitalised in the first 90 seconds of the encounter.
The rest of the first half would prove to be a grim affair before the Saddlers, thankfully, found their footing after the break.
Jacob Maddox's first display for the club brought a much-welcome increase in tempo and Knowles found the net in fine fashion.
His sweet left-footed strike was followed up by half-chances for either side and a draw, on the balance of play, seemed the fair result.