Brett Favre reacts after a sack. Favre only played a series in the Vikings’ 15-10 loss to the 49ers on Sunday in San Francisco.

San Francisco ? Brett Favre 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.

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.

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.

After that single series, Favre headed to the bench and gave way to backup Tarvaris Jackson

Alex Smith, Favre’s 49ers counterpart, went 9-of-13 for 88 yards in a solid first half.

Smith bounced back a week after stumbling through a subpar outing in which he completed three of nine passes for 37 yards and only two first downs in a win at Indianapolis.