The last time the Chargers saw defensive end Jared Allen, he was wearing a smile as long as his mullet.
He sacked quarterback Philip Rivers twice. He scored on a 2-yard basket catch at the corner of the end zone.
“On the next series,” Rivers said, “I remember hearing him hollering, 'Hey, (Antonio) Gates! That was pretty sweet, wasn't it?'”
The Chargers face an old, familiar challenge Sunday at 1:15 p.m. when they open their season against the Minnesota Vikings at Qualcomm Stadium, meeting Allen for the first time since Dec. 2, 2007.
Allen, a former Kansas City Chief who plays on the right side, is the anchor of a new-look Vikings defensive line. All-Pro defensive tackle Kevin Williams, a nine-year Minnesota fixture, is suspended and will miss a game for just the third time in his NFL career.
Allen met the Chargers eight times over his four years with the Chiefs. He was traded to the Vikings following the 2007 season.
Rivers is anticipating the reunion with the defender, whom he said he respects and can usually count on for some playful banter during games.
"That's what half the interaction is on the field," Rivers said. "People think it's so fierce, but a lot of it is guys who have great respect for one another, just getting after it ... He plays the game like you play as a kid. He probably played that way in the backyard, growing up."
Left tackle Marcus McNeill will draw the assignment of limiting Allen, a high-motor pass rusher who also defends the run well. Since entering the league in 2004, Allen has 83 sacks, the most in the NFL over that span.
Running backs Mike Tolbert and Ryan Mathews will be among those to assist McNeill against Allen, but coach Norv Turner said McNeill will also have solo responsibility.
“I was definitely happy when Jared left the division,” left tackle Marcus McNeill said. “I wouldn't have to deal with him twice a year. But you know, you play everybody in this league, so I have to play him again.
"I know he's an incredible player. I've got to bring my A-game … You can never let your guard down against him because he's going to go 100 percent, 100 percent of the time.”