Baltimore Ravens have withstood a siege from the San Francisco 49ers to clinch Super Bowl XLVII by three points in New Orleans.

The Ravens made a fast start, with Anquan Boldin getting on the end of Joe Flacco's pass to pout them ahead with just under five minutes played.

The Niners replied with a field goal just before the end of the first quarter, in which they had been outplayed.

John Harbaugh's men went further ahead with seven minutes left on the clock for the second quarter, as Flacco once again threw the pass for Dennis Pitta to touchdown.

A piece of individual brilliance from Jacoby Jones then put the Ravens 29-3 ahead as the clock ticked down to half time.

David Akers kicked over before the buzzer to shave three points off the deficit, but it was the underdogs who were in complete control.

The 49ers kicked off the third quarter but were left standing as Jones returned it for a record-equalling 108-yard touchdown.

It looked like the match was heading only one way, until fate intervened. The lights at the Mercedes-Benz Superdome went out, with reports of an outside power source disrupting the flow.

In all, the match was stopped for just over half an hour, and when play resumed it was Jim Harbaugh's boys who had the bit between their teeth.

Michael Crabtree and Frank Gore both touched down in the third quarter and another field goal saw the score at 28-23 as the teams entered the final stretch.

The Ravens inched further ahead with an early field goal in the fourth quarter, but a brilliant scramble by Colin Kaepernick brought the scores to within three.

The 49ers searched desperately to claw back the deficit, but it proved to be too great a margin and the Ravens ran out 34-31 winners in the end.