Tricky Lewis Neal was a handful for the Saddlers and the former Preston man's blocked shot fell nicely for the United skipper to open the scoring. The Cumbrians should have been two up four minutes later but Cleveland Taylor blasted a shot over the bar - the first of a string of wasted Carlisle chances.
Peter Murphy unlocked the visitors defence to find Danny Graham who sent Joe Anyinsah through, but caught in two minds he delayed his shot and played the ball back to a surprised Graham who could only prod an effort wide of the post.
Anyinsah was at fault again minutes later, managing to steer the ball wide when it looked easier to score from six yards and Neal caught the bug on the stroke of half-time. Clear through on goal he blazed wide.
Walsall had a goal disallowed for offside in the 13th minute but there were no complaints and the closest the visitors came to threatening the home side's goal was in the 26th minute when a great save by Ben Williams denied Mark Bradley with a tip over the bar. The game seemed to be petering out until Sofiene Zaaboub picked his way into the box when the referee awarded the penalty alleging that Thirlwell had tripped him.
Thirlwell did his best to put United back in front but his 25 yard power-drive in the 86th minute was saved by the keeper and Mark Bradley almost nicked it for the visitors in the 88th minute with a 20 yard snap shot that flew millimetres over the top.