When Brett Favre came out of retirement and signed with the Minnesota Vikings two months ago, most figured the aging quarterback with a surgically repaired right arm would simply be asked to hand off to All-Pro running back Adrian Peterson.

The 19-year veteran is proving he can still air it out, too.

Favre looks to build on another impressive performance and help the Vikings open with a fifth straight win Sunday against the lowly St. Louis Rams, who try to avoid extending a franchise-record losing streak to 15 games.

As the career leader in touchdown passes with 472, Favre will one day be enshrined in the Pro Football Hall of Fame, but there were some concerns with his health when the Vikings signed him in August.

Favre suffered a partially torn biceps in his throwing arm last season with the New York Jets, and his nine interceptions to two touchdowns over the final five games led to four losses and cost the team a playoff berth.

He's put that disappointing stretch far behind him.

After passing for 301 yards and engineering an 80-yard drive that culminated with a 32-yard TD pass with 2 seconds left in a 27-24 win over San Francisco in Week 3, Favre was his vintage self against his former team Monday.

Favre, who turned 40 years old Saturday, completed 24 of 31 passes for 271 yards and three touchdowns without an interception in a 30-23 win over Green Bay. He had five completions of at least 24 yards.

"(Favre's) still got great command of the football," coach Brad Childress said. "Whether command is touch, or velocity, or being able to pump it-let it go, he still has great command of the football."

By completing 68.0 percent of his passes for 837 yards, eight touchdowns and one interception, Favre has helped lead the Vikings to their best start since opening with six consecutive wins in 2003.

He is avoiding the risky throws that have defined his career and trusts the strength of his arm.

"My arm feels great,'' said Favre, who passed for 167 yards and a touchdown in the Jets' 47-3 win over the Rams last season. "It didn't feel very good last year. I'm not going to make excuses.

"But my arm feels a lot better and I think it's showing.''

Minnesota needed Favre to carry the offense last week with Peterson having little luck running against the Packers' new 3-4 defense.

Peterson averaged 119.0 rushing yards in the first three games but was held to 55 yards and a touchdown on 25 carries Monday. His longest run of the night was 12 yards.

Peterson should have better success finding running room against a St. Louis team that ranks 24th in the league in rushing defense, allowing an average of 135.0 yards.

The Vikings and Rams haven't met since St. Louis' 41-21 win in the 2006 regular-season finale.

Very little has gone right for St. Louis (0-4) since then.

The Rams are 5-31 since 2007 and have lost 14 in a row since a 34-14 victory over Dallas on Oct. 19. They appeared to have a chance to snap the skid last Sunday at San Francisco trailing 7-0 at halftime, but went on to lose 35-0.

Kyle Boller made his first start since December 2007 and was ineffective, going 13 of 24 for 108 yards and an interception while leading an offense that produced only 177 yards.

Boller could be back on the bench this week if Marc Bulger (bruised rotator cuff) is healthy enough to return. Coach Steve Spagnuolo said Bulger's questionable for this game.

Whoever starts at quarterback will need to find a way to get the team's sputtering offense in gear.

The Rams, 31st in total offense (264.5), have already been shut out twice and are last in the league with 24 total points.

"We have to give ourselves a chance. We're not doing that," Rams fullback Mike Karney said.

It won't get any easier against a stout Minnesota defense.

The Vikings front four is the key to the defense, pressuring the quarterback and stuffing the run.

They sacked Aaron Rodgers eight times Monday and lead the NFL with 16 on the season. Minnesota's defense hasn't allowed a 100-yard rusher in 27 straight games and because of St. Louis' unproductive passing game, it will be keyed on stopping Rams running back Steven Jackson.

Jackson, who already has two 100-yard rushing games this season, ran for 142 yards and three touchdowns on 25 carries in the last meeting.