SAN FRANCISCO (AP) — Being back on the field again meant plenty to Brett Favre, no matter if it was only for a few minutes.

No matter that he completed one pass and also got clobbered on a sack that lost Minnesota 10 yards.

Favre’s highly anticipated first game back with the Vikings lasted all of four unspectacular plays and one series in a 15-10 loss to the 49ers in a nationally televised preseason game Sunday at Candlestick Park, the only NFL show of the night.

“I didn’t fumble a snap, completed a pass,” Favre said. “That’s a win for me.”

Favre completed a 13-yard pass to Adrian Peterson on his first play from scrimmage but was sacked by Pro Bowl linebacker Patrick Willis two plays later and the Vikings wound up punting. The 40-year-old quarterback took the field just four days after his first training camp practice of the year. He decided to return for a 20th season and make yet another run at a Super Bowl title.

“There’s no substitute for getting in a game, calling plays, having a 40-second clock that you have to pay attention to,” said Favre, admittedly a little stiff afterward. “They blitzed on the last play. We technically could have picked it up, I could have made a call, but the mind wasn’t working quick enough. … That was obviously not a positive play but it’s what you do with it from here on. I’ll look at the film. I would hate for that to happen the first game in real action against New Orleans.”

It’s hard to make much of the small sampling. Not that Favre’s numbers mattered to the Vikings, just thrilled to have him back.

Alex Smith, Favre’s 49ers counterpart, went 9 of 13 for 88 yards in a solid first half. Willis had four tackles playing only nine snaps.

After that single series, Favre headed to the bench and gave way to backup Tarvaris Jackson — who had been in line to be the starter before Jared Allen, Ryan Longwell and Steve Hutchinson flew to Mississippi early last week to recruit Favre back to the Twin Cities. Favre, sporting a 5-o’clock shadow peppered with gray, could be seen laughing on the sideline in the second half.

Coach Brad Childress had planned to give Favre 10 plays, but that changed when it took so long for the Vikings offense to finally get on the field.

Smith bounced back a week after stumbling through a subpar outing in which he completed 3 of 9 passes for 37 yards and only two first downs in a win at Indianapolis. David Carr and Nate Davis rallied the Niners to 34 straight points in the 37-17 victory.

He made do for a 49ers offense missing three of its biggest stars: receiver Michael Crabtree, tight end Vernon Davis and running back Frank Gore.

“We just came out against the No. 1 rush defense in the NFL and marched it down the field,” Smith said. “After last week, it was nice to come out and have some quick success and then end it with a score. … We’ve been doing it all summer in practice. It was nice just to finally go do it in a game scenario.”

Smith completed his first four passes for 48 yards and 5 of his first six on the Niners’ opening drive, including a 24-yard strike to backup tight end Delanie Walker that set up a 4-yard scoring run by rookie Anthony Dixon.

After all the drama that surrounds Favre each offseason — will he or won’t he really retire? — he’s back in his No. 4 jersey and told his teammates he’s as committed to this as ever.

And why not keep going?

Favre is coming off a year in which he threw for 4,202 yards and 33 touchdowns and established career highs for completion rate (68.4), quarterback rating (107.2) and fewest interceptions (seven).

Favre insists the Vikings’ success will ride on the play of Peterson.

“I played the best football of my career and it wasn’t enough,” Favre said, referring to the Vikings losing to the eventual Super Bowl champion Saints in the NFC title game.

He was booed by the crowd Sunday when running onto the field for the first time midway through the first quarter. Favre has been the Niners’ nemesis for years.

In late September last year, Favre hit Greg Lewis on a 32-yard touchdown with 2 seconds left as the Vikings stunned San Francisco 27-24 in Minneapolis. That was the first of six straight road losses — five in a row by a combined 19 points — for the 49ers that helped cost them a playoff trip and a winning season.

Davis, San Francisco’s No. 3 QB and fifth-round pick last year, completed a pretty 60-yard pass to Ted Ginn Jr. in the third quarter with his foot planted at the goal line when he released the ball. The pass set up Joe Nedney’s 28-yard field goal. Davis later had an 18-yard completion to Nate Byham.

Longwell kicked a 40-yard field goal early in the second quarter for the Vikings’ first points. Minnesota rookie quarterback Joe Webb broke loose up the middle for a 48-yard TD run with 1:54 to play, then Webb was sacked by Derek Walker in the end zone for a safety on the final play of the game.

Former Stanford star Toby Gerhart got his first of his four carries for Minnesota midway through the second quarter, a 3-yard gain. This marked the rookie’s first game back in the Bay Area since the Vikings selected him at No. 51 in the second round of this year’s draft. Gerhart, who rushed for 1,871 yards and 28 touchdowns for the Cardinal last year, also caught two short passes.