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

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

"Both teams had to deal with it," Ravens coach John Harbaugh said of the power outage. "They dealt with it better, obviously. They were able to turn the momentum of the game."

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 2001 season.

"We don't make anything easy," said Flacco, who has guided the Ravens to the playoffs in each of his five NFL seasons. "It was a hard-fought game on both sides.

"We gave the country a pretty good game to watch. Not to our liking necessarily but that's the way it goes sometimes and that's the way we do things."

Lead evaporated

Baltimore's lead evaporated because the 49ers' talented second-year quarterback, Colin Kaepernick, suddenly found the form that made him one of the league's most dangerous quarterbacks this season.

Despite a shaky first half, Kaepernick completed 16 of 28 passes for 302 yards and a touchdown. He also ran for 62 yards and a 15-yard touchdown on seven carries to finish behind Frank Gore (110 yards) as the 49ers' second-leading ground gainer.

Baltimore Ravens inside linebacker Ray Lewis celebrates with the Vince Lombardi Trophy after the Ravens defeated the San Francisco 49ers to win Super Bowl XLVII in New Orleans, Louisiana, on Sunday. [Photo/Agencies]

Kaepernick's rushing score with 2:57 left cut the Baltimore lead to 31-29 but his pass attempt on the two-point conversion attempt was incomplete.

A 38-yard field goal by Justin Tucker with 4:19 left in the game hiked the Ravens' lead to 34-29, setting the stage for what could have been a Super Bowl-record comeback by the 49ers.

But the Ravens' defense, anchored by retiring future Hall of Fame linebacker Ray Lewis, came up big when it had to with a goal-line stand and handed the 49ers' franchise its first Super Bowl loss after five victories.

'Lost momentum'

Baltimore linebacker Terrell Suggs said it was the "ultimate cake" to allow Lewis to go out a winner.

"There will never be another leader like him and we sent him out like his brothers," he said. "His legacy will go untainted."

Ravens tight end Dennis Pitta, who caught four passes for 26 yards and a touchdown, said the power outage, which left half of the overheard lights in the Superdome out, "felt like an hour".

"We lost a lot of momentum and, credit to them, they came storming back and played tremendous. But this team continued to fight and never quit ... Didn't make it easy, but it was fun."