Chargers have half a mindset to overwhelm the Bills 31-20 and earn first victory

The performance was nearly as picturesque as it was precise, Philip Rivers not throwing his first incompletion until the middle of the second quarter and his next after halftime.

It was a completion less than photogenic, though, that best summed up how well things went for the Chargers offense in the first half Sunday.

“Improvising, man,” running back Melvin Gordon said after the Chargers’ 31-20 victory over Buffalo. “The greatest know how to do it. He improvised and made it happen. … It’s crazy how he saw me. But kudos to him.”

With Buffalo defensive end Trent Murphy hanging from Rivers like an anchor, the quarterback somehow found Gordon with a ball he flipped while falling, the play going for eight yards to the Buffalo two.

Moments later, Rivers connected with Gordon again and the Chargers, one week after never leading in their opener, were up 28-3 on a day when they practically ran away and hid for victory.

“It felt good,” Gordon said of a first half so good that it turned the second half into an exercise in maintaining focus. “That just showed us what type of offense we can be. We know that, but it’s good to have confirmation.”

Through the first two quarters, Rivers was 15 for 16 for 178 yards and three touchdowns, two of which went to Gordon.

Six Chargers had caught passes and Austin Ekeler had 72 yards in six carries.

Gordon had added a 20-yard scoring run, matching his career high of three touchdowns in a game.

Needing a victory after losing their home opener to Kansas City and before facing the 2-0 Rams at the Coliseum, the Chargers came out and punched a wounded opponent on the chin.

“We’ve got something to build off of in a positive way,” Gordon said. “Hopefully, we keep it rolling.”

After punting on their first possession, the Chargers scored touchdowns on each of their next four, only twice facing as much as third down.

They also incorporated Mike Williams, their talented and towering young receiver, early this time.

Williams, who didn’t catch a pass until the fourth quarter in Week 1, scored his first career touchdown reception in the first quarter and had a 17-yard catch to convert a third and 12 to extend another scoring drive.

Williams made the latter grab before being twisted to the ground and losing his helmet. He stood and emphatically signaled first down.

“We feel like we have an offense that can do that every game,” he said. “We have the weapons. … We just gotta go out there and make it happen.”

Williams’ touchdown came on a 10-yard pass from Rivers. He leaped and caught the ball over Buffalo’s Vontae Davis and Jordan Poyer.

The play was one Rivers said he mentioned in meetings Saturday night when the Chargers were preparing. When the opportunity to make the call first presented itself Sunday, offensive coordinator Ken Whisenhunt did.

“It’s always good to get in the end zone,” said Williams, who is in his second season. “Playing in front of their crowd … they were loud. I feel like I calmed them down a little bit more after that.”

But the Bills, who lost their first game at Baltimore 47-3, clearly weren’t calmed by what was happening.

Davis, one of their starting cornerbacks, was not on the field or the sideline over the final two quarters and later announced he had retired.

“Pulled himself out of the game,” coach Sean McDermott said. “He communicated to us that he was done.”

So perhaps that also illustrates how overwhelming the Chargers’ performance was to begin this game.

After halftime, though, their momentum stopped as abruptly as their offense did. They finished the third quarter with three three-and-out drives and four yards.

“Second half came out a little flat,” coach Anthony Lynn said. “But I’d rather learn this way than the other way, to come out and finish the games a little better than what we did.”

Given the Bills’ struggles and the play of the Chargers defense, the lull proved to be nothing more than a little concerning.

Not that the winners were content in victory.

“When we’re up, we kind of let off the gas a little bit,” Gordon said. “We gotta learn how to take their will. The great teams know how to do it. … We gotta figure that out.”

For one week, at least, the Chargers figured out enough in the first half for it not to matter.

jeff.miller@latimes.com