ORCHARD PARK — For the second consecutive week, the San Diego Chargers stated their case to join the debate for Western supremacy.

A week after knocking off NFC West power and defending champion Seattle, the San Chargers traveled cross country and dominated the Buffalo Bills, 22-10, at blustery Ralph Wilson Stadium. The victory, fueled by Philip Rivers’ two touchdown passes and a dominant defense, enabled the Chargers to improve to 2-1 and win for the fourth time in their last six East Coast visits.

Rivers completed 18 of 25 for 256 yards for the victors. His most productive targets were wide receiver Eddie Royal, who caught touchdown passes of three and five yards, and wide receiver Malcom Floyd, who had two catches for 98 yards.

“We’re all just playing around Philip,” Floyd said. “He breaks down the defense and he knows where to go and we kind of know where it’s going to go, pre-snap, just based on coverage. We’re just really fortunate to have the greatest quarterback in the league.”

The Chargers also showed their teeth on the other side of the ball, holding the 2-1 Bills to 87 yards rushing, 76 below their season average.

San Diego recorded three sacks of EJ Manuel and rushed him into a safety late in the game. Manuel finished with 23 completions in 39 attempts for 238 yards and one touchdown. Bills rookie wide receiver Sammy Watkins was held to just two catches for 19 yards, a week after he had eight receptions for 117 yards and a touchdown against Miami.

San Diego was able to move the ball without its top two running backs — Ryan Mathews, who was inactive with a knee injury, and Danny Woodhead, who left the game in the first quarter with an ankle injury. Donald Brown stepped in and rushed for 62 yards on 31 carries.

“I feel good,” Brown said, after the heavy workload. “Tomorrow, I’ll probably be sore, but whatever it takes to get a win. We knew it was going to be a grind and it was. (They have) a phenomenal front four, the linebackers were aggressive and their safeties, too, so it was a grind and we do whatever it takes to get a W.”

The Chargers took a 7-0 lead on a 3-yard touchdown pass from Rivers to Royal with 9:45 left in the first quarter. The big play in the seven-play drive was a 49-yard bomb from Rivers to Floyd that advanced the ball to the Bills’ 24.

San Diego improved its lead to 10 on Nick Novak’s 19-yard field goal. The 17-play, 91-yard drive was aided by two defensive penalties and saw Rivers complete passes of 23 yards to Royal, 13 yards to running back Donald Brown and 20 yards to tight end Ladarius Green.

The Bills broke into the scoring column on a 45-yard field goal by Dan Carpenter with 2:56 remaining in the half. The kick capped an eight-play, 65-yard scoring drive that featured a 21-yard catch and run by running back Fred Jackson and a 37-yard completion from EJ Manuel to tight end Scott Chandler.

San Diego answered with a 37-yard field goal by Novak with 21 seconds left in the half. The big play in the seven-play, 61-yard drive was a 49-yard completion from Rivers to Floyd.

The Chargers drove 80 yards in 14 plays in their first series in the second half and went up 20-3 on a 5-yard touchdown pass from Rivers to Royal. Rivers had completions of 14 and 26 yards to Green on the drive.

Buffalo closed the gap to 10 with 1:16 left in the third on an 11-yard touchdown pass from Manuel to Jackson. Manuel completed 4 of 5 passes for 40 yards and also had an 8-yard scramble on the drive. But the hole the Bills had dug proved too big to climb out of.

“That’s not where you want to be ever,” Bills defensive tackle Kyle Williams said when asked about the deficit. “It’s always difficult to play from behind.”

San Diego picked up a safety with 3:23 left in the game when defensive end Corey Liuget pressured Manuel in the Bills’ end zone and the second-year quarterback threw the ball away to an area where there wasn’t a Buffalo receiver.

“We didn’t make plays,” said Jackson, who finished with 78 yards on eight receptions, but rushed for just 34 yards. “We made plays in the first two weeks, but we didn’t make any today. That’s probably the difference in the game.”

What the Chargers said:

“He’s just a great competitor and a great leader. It’s really an honor to play with him.” –Running back Donald Brown on quarterback Philip Rivers

What we learned about the Chargers:

1. West Coast teams lose about 70 percent of their games in East Coast stadiums. But the San Diego Chargers are bucking that trend. Sunday’s 22-10 victory in Buffalo marked the fourth time in their last six cross-country trips that the Chargers have emerged victorious. “Don’t know what it is,” wide receiver Malcolm Floyd said. “We just travel well.”

2. Donald Brown can handle a heavy workload. Running back Ryan Mathews was on the inactive list, and then Danny Woodhead went down with an ankle injury before the game was four minutes old. Coach Mike McCoy decided to ride Brown after that. The 5-foot-10, 207-pound six-year veteran out of Connecticut carried 31 times for 62 yards and also had five catches for 27 yards. “Yeah, 36 touches is a lot,” said quarterback Philip Rivers. “Donald is a true pro, takes care of his body and he is going to be getting the load of it here for the next while.”

–RB Danny Woodhead suffered what might be a season-ending, broken fibula Sunday as San Diego’s running back corps got a little thinner. Woodhead, a seventh-year veteran from Chadron State, had gotten the starting nod in place of Ryan Mathews, who will be sidelined for an extended period with a strained MCL. But Woodhead’s day was through after just one carry. With 11:37 remaining in the first quarter, he was carted off the field and did not return.

–QB Philip Rivers is an equal opportunity distributor. A week after hooking with tight end Antonio Gates for three touchdowns, Rivers connected with Eddie Royal for touchdowns from three and five yards out. The 11th year veteran also found Malcolm Floyd twice for 98 yards and Ladarius Green four times for 64 yards. Rivers finished with 18 completions in 25 attempts for 256 yards and two scores — a robust 131.4 quarterback rating.

–K Nick Novak extended his field goal streak to 23 straight with kicks from 19 and 37 vs. the Bills. The seven-year veteran from Maryland is 4-for-4 this season 38-for-41 the past two years. During that span, he’s converted all 13 of his attempts from 40 and beyond.

What the Bills said:

“It’s Week Three. You don’t overreact, and you don’t go in and try to revamp everything. You come in and you go back to work. We lost to a good team this week. They came out and made plays.” –Running back Fred Jackson

What we learned about the Bills

1. Talk about them having turned the corner might have been a bit premature. Admittedly, San Diego was a tough opponent, but the Bills didn’t help their cause, making numerous mistakes that reminded some of the bad, old days. They were flagged 11 times for 101 yards in penalties, and a few of the calls wiped out sizeable gains and killed drives. “I’m not taking anything away from them,” said defensive tackle Kyle Williams of the Chargers. “They beat us and they played better than we did today, but we didn’t help ourselves.”

2. Wide receiver Sammy Watkins is experiencing the ups-and-downs that come with the education of a rookie. He was targeted eight times and wound up with just two catches for a harmless 19 yards. The performance came a week after being named the AFC Rookie of the Week for his eight-reception, 117-yard, one-touchdown performance vs. Miami. “They played a very good scheme,” Watkins said of San Diego. “Sometimes they doubled me and sometimes they didn’t. We didn’t finish.”

–RB C.J. Spiller continues to struggle. He managed just 25 yards on 10 carries Sunday and now has just 147 yards on 37 carries, a 3.9 yards-per-carry average. That’s more than half-a-yard below last year’s average and just over two-yards per carry below his 2012 numbers. He’s on a pace to rush for just 784 yards. If you take away his 47-yard gain, he’s averaging just 2.7 yards on his 36 other carries.

–RB Fred Jackson had a productive day against San Diego, rushing six times for 34 yards and catching eight passes for 78 yards and one touchdown. His 112 yards of offense was nearly as much as he combined for in his first two games (125). His 11-yard touchdown reception in the fourth quarter gave him 35 touchdowns for his career, tying him with Cookie Gilchrist for eighth place on the Bills all-time touchdown list.

–The Bills offensive line played fairly well its first two games, but regressed against the Chargers, who boasted a weaker front seven than Buffalo’s first two opponents — the Bears and Dolphins. After opening holes for an average of 153 yards, its first two games, the Bills o-line cleared the way for just 87 yards vs. San Diego. And, after allowing just one sack its first two games, it yielded three against the Chargers, though, at least two of those sacks were the result of EJ Manuel holding onto the ball too long.