EDEN PRAIRIE — Antoine Winfield shook his head and winced. As one of the NFL’s surest tacklers, he’s not used to whiffing.

“That’s definitely not the example I want to set for the younger guys,” the Minnesota Vikings cornerback said. “That’s not something I want to put on film. You’ll see — trust me — a better effort out of our defense this week.”

Winfield and fellow cornerbacks Cedric Griffin and Chris Cook held their own in pass coverage against San Diego’s wide receivers, keeping quarterback Philip Rivers from going deep. But after doing the hard part well, the Vikings let the Chargers move the ball in the pivotal second half of last Sunday’s season opener by completing a bunch of second-option short throws to running backs and tight ends — and many times failing to tackle the receivers right away.

“It’s mostly our fault,” said Winfield, the 5-foot-9, 180-pound, 13-year veteran who has long been one of the toughest players in the league despite his size.

So this week, the Vikings have taken a back-to-basics approach on defense. Most of it is mental.

“You can hit the dummies or whatever, but it’s not realistic,” Winfield said. “You don’t have guys diving or cutting or whatever. It’s just proper technique. Bending your knees, and wrapping up.”

Winfield missed two tackles, by his estimation. When was the last time that happened?

“Ooh, I really can’t remember. It’s been a while. I’m not happy about that,” Winfield said.

Linebacker Chad Greenway, another standout, let a couple of players slip past him. Safety Jamarca Sanford, another hard hitter who has parlayed strong special teams play into a starting spot, let Chargers fullback Mike Tolbert run right through him near the goal line on his way to a touchdown run in the third quarter.

“It’s just one of those games. You have games like that,” Sanford said. “We know what it takes to get better. We’re going to go out and fix that problem.”

This week, the Vikings host Tampa Bay, and the Buccaneers feature a couple of big bodies to bring down in quarterback Josh Freeman and running back LeGarrette Blount. Freeman is listed at 6-foot-6 and 248 pounds. Blount is 6-foot and 247 pounds.

This is, then, the perfect time to refine the skill.

“It’s hard to play defense in the NFL if you don’t tackle well, particularly the way we’re structured on defense,” head coach Leslie Frazier said. “So it’s something that we have to improve in order to have the type of team we want to have.”

In the “Tampa Two” scheme the Vikings have run since 2006, passes are preferably diverted toward the middle of the field, in front of the secondary.

That puts sure tackling and quick reactions at a premium. Yards after the catch can be costly, as the Chargers reminded them last week, particularly on a couple of crucial third downs.

“The effort was there. Guys were running around. When the opportunity is there, you’ve got to make it happen,” defensive end Jared Allen said.

This, after all, is the root of why guys love to play this sport. It’s an instinct just as much as it is a developed and practiced technique.

“You’ve got to tackle. Playing defense, if it’s not one of your strengths, you’re not going to be around much,” Sanford said.

As Greenway noted, missed tackles were common all over the league last week, one reason yards passing were so high in many games. Sanford said some of this could be attributable to the first round of regular-season action, a clear crank-up in intensity from low-contact drills in training camp and minimal participation in preseason games.

“It’s something you’ve got to be concerned about it,” Greenway said. “It’s something you’ve got to go out and work on.”

NOTES: The Vikings at least emerged from their opener unscathed, health-wise, unlike the Chargers, who lost PK Nate Kaeding and DE Luis Castillo to serious injuries in that game. Backup DE Adrian Awasom (knee) was the only player who didn’t participate in Wednesday’s practice for the Vikings. … Starting RG Anthony Herrera didn’t appear to be moving that well during Sunday’s game, but said his surgically repaired left knee is in “great” shape, as is he. “I surprised myself. I wasn’t tired at all,” Herrera said. He insisted he’s fully able to pull in either direction and “do whatever I want to do.” … The Vikings have filled their open practice-squad spot with Cedric McKinley, the former DE who was let go for a week before being brought back.