By Steve Ginsburg

NEW ORLEANS (Reuters) - The Baltimore Ravens survived a furious second-half rally by San Francisco and a momentum-sapping power outage at the Superdome to defeat the scrappy 49ers 34-31 in the Super Bowl on Sunday.

A Super Bowl-record 108-yard kickoff return for a touchdown by Jacoby Jones gave the Ravens a 28-6 lead early in the third quarter but the 49ers scored 17 straight points after a 35-minute power outage and nearly pulled off a stunning comeback.

Trailing 34-29, the 49ers marched down to the Ravens' seven but failed to score on four tries, surrendering the ball on downs at the five with less than two minutes remaining.

Baltimore used up the clock and on fourth down, punter Sam Koch ran out of bounds in the end zone for a safety with four seconds left.

Joe Flacco, the game's Most Valuable Player, completed 22 of 33 passes for 287 yards, three touchdowns and no interceptions to lead the Ravens to their first title since the 2000 season.

(Editing by Frank Pingue)