Walsall suffered a crushing defeat at the hands of 10-man Oxford United as goals from Rob Dickie, Luke Garbutt and Jerome Sinclair gave the visitors all three points.
The U's went ahead when Garbutt swung the ball to the far post where Dikcie was left unmarked and the towering defender was there to just nod the ball into the ground and past Liam Roberts.
But United weren’t in the lead for long - just seven minutes.
Following a flick around the defender by Josh Gordon, Curtis Nelson failed to deal with the ball and Cook capitalised by poking his foot around the Oxford defender, with the ball then ending up in the back of the net.
On the stroke of half-time, the visitors were reduced to 10 men as Marcus Browne saw a straight red for a rash challenge on Zeli Ismail.
Into the second half and despite having one man fewer, the visitors took the game to the Saddlers and just after the hour mark, Oxford made their pressure count.
A bursting run from Sam Long saw him get in behind Corey Blackett-Taylor before squaring the ball to Garbutt at the back post who had a simple task to place the ball back across Roberts and into the bottom corner.
In the final minute of the game, the visitors extended their lead and added a third goal as substitute Sinclair slotted the ball under Roberts to close the game out.