A surprise onside kick sparked the Saints' second-half comeback. Their 25th-ranked defense made several key stops, and Tracy Porter's 74-yard interception return on a pass from Manning, of all people, clinched it.Manning gave futile chase, but was blocked by a New Orleans defender and fell awkwardly as the cornerback raced by The four-time NFL MVP forlornly walked to the sideline as the Big Easy celebrations began Who would have thought the biggest mistake of the game would have come from Manning?.