The NFL acknowledges that one of the game officials should have noticed that 18 seconds were incorrectly run off the clock late in the fourth quarter of Pittsburgh's 24-20 victory at San Diego.

League spokesman Michael Signora says in a statement emailed Monday that "an error by the clock operator" after a touchback allowed extra time to run off, and "it is the responsibility of the side judge to supervise the timing of the game."

The statement adds: "Had the side judge or any of the other six on-field officials noticed the timing error, they could have corrected it."

The NFL will review the work done by the clock operator and game officials.