ORCHARD PARK, N.Y. -- The Cincinnati Bengals are off to their best start in 27 years, but quarterback Andy Dalton believes they can still play better.

How good can be the Bengals be at their best?

"Well, you wouldn't throw an incompletion, you would score every time you hand the ball off," Dalton said with a smile.

Short of that, the Bengals will settle for being 6-0 after beating the Buffalo Bills 34-21 on Sunday at Ralph Wilson Stadium.

The Bengals have started 6-0 twice before, in 1975 and in 1988, when they advanced to the Super Bowl.

Coach Marvin Lewis called the milestone "a miniscule part of history."

"We've got bigger things to do," Lewis added.

The Bengals offense had its highest-scoring day of the season, even with the Bills blanketing star receiver A.J. Green (four catches, 36 yards). Dalton completed 22 of 33 passes for 243 yards and three touchdowns, connecting with seven different receivers for first downs or touchdowns.

Cincinnati wide receiver Marvin Jones exploited the one-on-one coverage created by the extra attention Green received and caught a career-high nine passes for 95 yards and a touchdown.

Tight end Tyler Eifert and running back Jeremy Hill also caught touchdown passes from Dalton, running back Giovani Bernard ran for a touchdown, and Matt Nugent kicked a couple field goals.

"You never know who is going to have the big week," Dalton said. "It's nice to have the ability to spread it around to a bunch of different guys, because we have a lot of playmakers on this team."

Bills coach Rex Ryan said the Bengals had too many weapons for his defense to contain.

"That team has lit up everybody in the league," Ryan said. "You can take away this guy, you take away that guy, well, this other dude beat you."

The banged up Bills began the game without starting quarterback Tyrod Taylor (knee) and wide receiver Percy Harvin (hip), and finished without top receiver Sammy Watkins (ankle), Pro Bowl defensive tackle Kyle Williams (knee) and right tackle Seantrel Henderson (concussion).

Backup Bills quarterback E.J. Manuel completed 28 of 41 passes for 263 yards, one touchdown and an interception in his first start since the fourth game of last season. Manuel also rushed for 22 yards and a touchdown.

"It's been a long time," Manuel said. "It went all right, but at the end of the day, we didn't win. Performance-wise, of course there are some things I want to do better. But I thought it was solid."

The Bills got running back LeSean McCoy (90 rushing yards, one touchdown) and Watkins (four receptions, 48 yards, one touchdown) back in the lineup after both missed the past two games. But by halftime, Watkins was on crutches after he injured his left ankle on the touchdown catch.

After benefiting from a short field early on, Dalton directed long touchdown drives on the first two series of the second half and put the game away with a 4-yard touchdown pass to Eifert that made it 31-14 late in the third quarter.

The Bengals began the second half with their worst field position of the game, but drove 90 yards to extend their lead to 24-14 on Dalton's 10-yard touchdown pass to Jones, who also had a 42-yard reception two plays earlier.

The Bills got within two touchdowns with less than seven minutes to play on McCoy's 4-yard scoring run.

Cincinnati had an average drive start at midfield in opening a 17-14 halftime lead.

Hill took a swing pass from Dalton and ran 13 yards to tie the game at 7-7 late in the first quarter. The Bengals began their drive at midfield after a 15-yard taunting penalty on Buffalo's Ron Brooks during a punt return.

Bernard's 17-yard touchdown run put the Bengals up 14-7 early in the second quarter. In his first series of action, Bernard turned three touches into 46 yards on the 55-yard scoring drive, the Bengals' longest of the half.

Nugent's 47-yard field goal made it 17-7 with seven minutes left in the half. The Bengals took possession at the Buffalo 36 after a 15-yard facemask penalty on Buffalo's Marquise Goodwin during a punt return.

Buffalo opened the game with an 80-yard drive capped by Manuel's 2-yard touchdown run, and closed the half with an 86-yard drive that culminated with Watkins' 22-yard touchdown reception. In between those drives, the Bills did not gain a first down on four series.

NOTES: The Bills, who entered the game leading the NFL with 54 accepted penalties for 490 yards, were flagged eight times for 93 yards. ... Bengals LB Vincent Rey injured his right ankle during the third quarter. ... Cincinnati CB Leon Hall was inactive due to a back injury. Every other player listed on the Bengals' injury report was active. .... TE Charles Clay led the Bills with nine receptions for 62 yards. ... The 3-3 Bills boarded a plan for London following the game in preparation of next week's matchup with the Jaguars, who are scheduled to fly out Thursday.