Looking for a spark in the second half of the season, the Green Bay Packers and San Francisco 49ers have been rejuvenated after recording much-needed victories last week.

Both teams look to build on that momentum while the Packers try for an eighth consecutive victory over the 49ers on Sunday at Lambeau Field.

While Green Bay (5-4) avoided a third straight loss with an aggressive defensive effort in a 17-7 win over Dallas last Sunday, San Francisco benefited from five Jay Cutler interceptions and snapped a four-game losing streak with a 10-6 win over Chicago on Nov. 12.

"It was a big relief," 49ers tight end Vernon Davis said. "It's truly a blessing to be able to get this. We just have to keep winning."

The victory helped keep the 49ers (4-5) in the NFC playoff mix, one game behind the Packers, who moved into a four-way tie with Philadelphia, New York and Atlanta for the two wild card spots.

"(It) won't mean anything if we don't win (this) week," said Packers cornerback Charles Woodson, who forced two fumbles and had an interception against the Cowboys. "It could be fun the rest of the season. But it could also be tough if we don't do what we need to do."

What Green Bay will try to do is continue its success over San Francisco, which hasn't beaten the Packers since a 24-20 win at Lambeau on Nov. 4, 1990.

After this contest, the Packers have a winnable game at Detroit on Thanksgiving before facing a difficult stretch against Baltimore followed by games at Chicago and Pittsburgh.

It was Green Bay's defense - ranked fourth in league allowing 282.3 yards per game - that made the difference against Dallas. The Packers sacked Tony Romo five times and allowed the Cowboys to convert only three of 12 third-down chances while holding them to 283 yards and a late fourth-quarter touchdown.

Green Bay, allowing 19.9 points per contest, had given up 76 points total in losing their previous two games to Tampa Bay and Minnesota after yielding a field goal in blowout wins over Cleveland and Detroit.

"It's well-documented what's gone on the last two weeks," Green Bay coach Mike McCarthy said. "We were able to learn from that, carry it forward to our game (last weekend), and we need to take that forward to San Francisco."

The Packers have a chance for another solid defensive effort against the 49ers, who rank 27th in total offense (277.9 yards per game) and 21st in scoring (20.4 points).

Green Bay's defense should get a boost with the expected return of linebacker Aaron Kampman, who sat out last weekend from the effects of a concussion.

Offensively, the Packers still need to do a better job of protecting quarterback Aaron Rodgers. He was 25 of 36 for 189 yards and a touchdown, but was sacked four times by the Cowboys. Green Bay has a allowed a league-high 41 sacks.

It's uncertain if a knee injury will again keep veteran offensive tackle Mark Tauscher out of the lineup Sunday. McCarthy, however, felt rookie T.J. Lang played well in Tauscher's place last weekend.

Rodgers, who had thrown at least two TDs in six straight games before last week, faces a San Francisco defense which also was the difference in its latest victory.

After failing to force a turnover in their previous two games, the 49ers' recorded a season high with the five interceptions and held the Bears to 43 yards rushing.

Despite throwing for 118 yards, Alex Smith won for the first time in eight starts dating to a 17-16 win over St. Louis on Sept. 16, 2007. Frank Gore rushed 25 times for 104 yards and the game's only touchdown during his second 100-yard game of the season.

After rushing for more than 1,000 yards each of the last three seasons, Gore has gained 551 this season and scored in three straight contests.

Gore ran for 130 yards and a touchdown on 18 carries in a San Francisco's 30-19 loss to Green Bay in the teams' most recent meeting on Dec. 10, 2006.