Vikings defensive end Jared Allen was trying to find a word to describe the way he was feeling, his frustration after his team hit another second-half wall. He stopped in mid-discussion when it appeared none of the words he was considering was worthy of a family audience.

"So I'll listen to my mom and not say nothing on that," he said.

The numbers spoke loudly enough. For the second consecutive week the Vikings saw a second-half lead evaporate into a loss. In San Diego last weekend the Vikings led 17-7 at halftime in a 24-17 loss.

On Sunday, they led 17-0 at halftime and lost 24-20.

"We were dominating 'em in the first half," Allen said. "We were playing like we know we can. We have to find a way to play for 60 minutes."

How could the Buccaneers go from three first downs in the first two quarters to 17 points on their final three drives?

"It didn't really seem like they did a lot of things differently," linebacker Chad Greenway said. "They started to get a little momentum, and we couldn't get a stop when we had to. We can't excuse it away."

The Vikings defense started the game when Allen blew around Bucs tackle Donald Penn to sack quarterback Josh Freeman on the first play. And that's how the first half went, with the Vikings limiting Tampa Bay to 62 yards of offense.

But things changed. Losing nickel back Chris Cook to a groin injury in the second quarter didn't help. The Buccaneers also used a little no-huddle coming out in the third quarter. But perhaps the biggest difference was Tampa was able to get running back LeGarrette Blount going, putting a damper on the Vikings pass rush.

"They began to run the ball more effectively, which makes those guys have to slow down a little bit," Vikings coach Leslie Frazier said.

The Bucs scored in two plays on their first third-quarter series, when Blount burst through the line for a 27-yard scoring play. Freeman, meanwhile, was finding his rhythm -- and his receivers. In two fourth-quarter TD drives he was poised. His 25-yard TD pass to Arrelious Benn came after Benn beat Vikings corner Cedric Griffin. On the final scoring drive Freeman was 5-for-6 for 46 yards, hitting receiver Preston Parker three times, running back Earnest Graham and tight end Kellen Winslow once each.

Adding to the problems were key penalties. Defensive end Brian Robison's offside came at a bad time during Tampa's third-quarter drive for a field goal. Allen was called for roughing the passer the play before Freeman hit Benn.

"We came out a little lazy [in the second half]," Griffin said.

The Vikings had a key interception that could have changed the game's momentum. It came after the Bucs had pulled within 17-7 in the third quarter, then successfully executed an onside kick. Tampa drove to the 12 before Freeman's pass for Winslow was intercepted by Husain Abdullah.

Turns out it only delayed the inevitable.

"This is pathetic," Allen said. "To have a one-point lead in the fourth quarter and blow it? With this defense? Jiminy Crickets."