Philip Rivers, Chargers show they are contenders in AFC West

Philip Rivers proved clutch in the second half for the Chargers after throwing two interceptions before halftime. AP Photo/Denis Poroy

SAN DIEGO -- Stevie Johnson said he signed with the San Diego Chargers in free agency for moments like this -- a come-from-behind 33-28 win in the team’s home opener against the Detroit Lions on Sunday.

“It just solidifies how special this team is -- even though it’s only Week 1,” Johnson said.

Another free-agent addition, tackle Joe Barksdale, remarked that it felt good to be on a winning team after toiling in mediocrity with the St. Louis Rams for three seasons.

Momentum is a strange and fickle thing. But even after falling behind 21-3 in the second quarter, Johnson said he and his teammates didn’t panic.

And that patience comes from having a quarterback the caliber of Philip Rivers on your side. He has been in dire situations too many times to count, and understands how to engineer important drives during meaningful moments.

“Knowing that Philip is my quarterback is knowing that we’ve got action no matter what,” Johnson said. “We were down 21-3, but we still felt like we’ve got action. So that’s what it is here with a quarterback like No. 17 and the boys that we have on this team -- we’re never out of it.”

Rivers stunk in the first half, throwing two interceptions -- including one that should have been airmailed into the sixth row of the stands but instead ended up as a 31-yard interception for a score by ball-hawking Detroit safety Glover Quin.

“It was a terrible throw,” Rivers said. “There’s no other way to describe it.”

But like most elite quarterbacks, the 33-year-old signal-caller has a short-term memory. After the Chargers fell behind by 18 points, Rivers led the Chargers to points on five of the final eight drives as San Diego reeled off 30 straight points in taking over the game.

“He’s a Hall of Fame quarterback, man,” Lions defensive end Darryl Tapp said. “He is able to figure out the things on the offensive side of the ball, on their side, to kind of get us guessing a little bit and was able to capitalize.”

The heavyweights of the AFC West, the Denver Broncos led by an aging Peyton Manning, looked beatable in a 19-13 win at home against the Baltimore Ravens.

The Kansas City Chiefs, widely considered to be an AFC playoff contender, earned a solid win on the road against the Houston Texans.

And the Raiders looked like, well, the Raiders, losing at home to Cincinnati 33-13 and, even worse, potentially losing second-year quarterback Derek Carr for an extended period with a hand injury.

The Chargers haven’t won the AFC West since 2009, but San Diego has a potent offense and an improving defense that held electric Detroit receivers Golden Tate and Calvin Johnson to a combined six catches for 63 yards and no touchdowns.

In perhaps the team’s final season in San Diego, the Chargers could be poised for a memorable 2015.

“Wins like this tend to ascend it in a hurry, as far as the camaraderie,” Rivers said. “You just come closer together when you have to fight and win a game like this. … You get out here and it all becomes real when you know the end result that the final score is going to count.”