Marc Tierney was sent off and Colchester were punished as Oldham battled back to draw 2-2.
Ten-man Us held on travels to Boundary Park
Marc Tierney was sent off and Colchester were punished as Oldham battled back to draw 2-2.
Tierney's 56th-minute red card was the turning point as Oldham laid siege to the Colchester goal and equalised two minutes from time through Ryan Brooke.
United took an early lead when David Fox drilled his shot inside the near post from 10 yards.
Kayode Odejayi doubled his side's advantage with a deft header, but former Oldham defender Tierney was sent off five minutes later when he was shown a second yellow card for kicking the ball away.
Chris Taylor pulled a goal back from the penalty spot after being fouled by Magnus Okuonghae and teenager Brooke completed the comeback with a diving header to convert Keigan Parker's cross.
Danny Whitaker almost won it for the home side right at the death but Ben Williams produced a fine save to deny him.