Conor Wilkinson's first goal for Oldham Athletic on what is his last appearance for the club before he returns to his parent side Bolton Wanderers has sent the hosts into the break level at 1-1 with Walsall.
The visitors were on the back foot during the opening exchanges, but with 10 minutes played, they broke the deadlock.
Cook then had the chance to double his tally just three minutes later, but his volleyed effort from the edge of the area flew just over the crossbar.
Meanwhile, up the other end, Wilkinson stung the palms of Richard O'Donnell from distance. However, the Walsall goalkeeper was powerless to prevent Wilkinson from breaking the deadlock in the 31st minute. Carl Winchester played in Mike Jones, who in turn found Wilkinson and the youngster stroked the ball in.
Then, just two minutes later the ball again dropped kindly for Wilkinson, but on this occasion his effort struck the side-netting.
Oldham ended the half in the ascendancy, but Walsall, who have not won away all season, held firm.