SAN DIEGO — Jack Del Rio’s eyes lit up, his voice boomed, and he couldn’t help but grab general manager Reggie McKenzie to give him a joyful shake.

“Hey!” Del Rio yelled as the two large men met at the doorway of the Raiders locker room Sunday afternoon. “Hey, hey!”

Nothing else really needed to be said because every statement necessary was made during the Raiders’ decisive 37-29 victory at Qualcomm Stadium.

Hey, they might be a good team. Now. Presently. Can you believe it?

Hey, the Raiders fired out to their best start in years, stormed to a 37-6 lead by the third quarter, and cruised to this victory to raise their record to 3-3.

Hey, rookie receiver Amari Cooper was the best player on the field and the Raiders’ offensive and defensive lines were in total control.

Hey, hey, everything the Raiders did for three quarters worked and afterward the Raiders leaders looked as happy and confident as I can ever remember.

Del Rio’s coaching is working. McKenzie’s roster is building steam. Owner Mark Davis’ plan — wherever the Raiders are based after this season — is coming together.

“I think (for) three quarters you saw a glimpse of a good football team,” Del Rio said. “All three phases, playing well.”

Safety Charles Woodson, who is not prone to gushy overstatement, put it this way: “As far as the first three quarters, that was as well as we could’ve played.”

Really, it was about as well as anybody in this league has played, and it came on the road, in the division, right after two tough losses and then the bye week to stew over them.

Derek Carr, what was the locker room like after this game?

“It was joyful,” the Raiders quarterback said. “It was definitely joyful.”

Granted, this huge Raiders performance came against a wounded Charger team, in front of a San Diego crowd that was perhaps 50 percent Raiders fans, and the Raiders’ eased up enough in the fourth quarter to let the Chargers almost put this in danger territory.

Not a perfect game. Only brings them to .500, not quite in a playoff slot, with many ways left to screw this all up. And Denver is still far ahead in the AFC West.

But, coming from where the Raiders have been for more than a decade, the sight of Cooper blowing through the defense, Carr throwing darts and linebacker Malcolm Smith showing up all over the field … that’s solid proof of tangible improvement.

Can they keep doing this? We shall see.

But you can’t do it twice or three times if you’ve never done it once, and now the Raiders — for the first time at least since 2010 — have done it once.

That’s proof of something, and Del Rio, especially, needed it.

Yes, the atmosphere in the Raiders locker room is different, largely thanks to Del Rio’s arrival this season.

Yes, the players are better, thanks to McKenzie’s recent moves.

But after the tight losses to Chicago and Denver, the Raiders needed something to validate the talk and the anecdotes.

They needed a big win, and they needed it against a division rival.

Now … does Del Rio want his players thinking about the AFC playoff race?

“We talked from Day 1 about our No. 1 goal was to win the division — you have to win in the division to have a chance to win the division,” Del Rio said.

“We don’t sit and fixate on it every day — we can see the numbers, we know there’s a team (Denver) that’s undefeated right now …

“But what we’re going to focus on now is to be a good football team and demanding, developing, growing as an organization, as a football team. I’m proud of our guys because I see plenty of good signs of growth.”

The signs were everywhere on Sunday, from start to finish.

After Del Rio finished his postgame presser, Davis saw him down the Qualcomm hallway, called out Del Rio’s name and theatrically wiped his brow in exaggerated relief.

Del Rio just laughed, then grabbed his owner and gave him a happy shake, too.

“We’re doing so many good things,” Del Rio said at his presser. “We know that there are good things ahead.”

They needed this one, though, to prove it to everybody watching, and to themselves. They needed to play like one of the best teams in the league — if only for three quarters — to show that this is workable.

The Raiders are possibly a good team. It’s foolish to deny that now, and still amazing to actually type those words.

Read Tim Kawakami’s Talking Points blog at blogs.mercurynews.com/kawakami. Contact him at tkawakami@mercurynews.com or 408-920-5442. Follow him on Twitter at twitter.com/timkawakami.