The Pittsburgh Steelers needed a touchdown with 42 seconds left in Sunday's Super Bowl to defeat the upstart Arizona Cardinals 27-23, dpa reported.
The victory in Tampa, Florida, makes Pittsburgh the first franchise to record six NFL titles in the Super Bowl era.
Arizona trailed 20-7 midway through the fourth quarter before scoring 16 unanswered points - including a rare safety - to take the lead for the first time with less than three minutes to play.
The Steelers drove 78 yards in eight plays, capped by quarterback Ben Roethlisberger's 6-yard fade pass to wide receiver Santonio Holmes, who had nine catches for 131 yards in the game and was honoured as Super Bowl most valuable player.
Video replays showed that Holmes, surrounded by three Cardinal defenders in the right corner of the end zone, had barely tapped both feet before falling out of bounds as he clutched the ball with his body fully extended.