ORCHARD PARK, N.Y. (AP) - Linebacker Derrick Johnson isn't going to apologize for the Kansas City Chiefs' perfect start. "I've heard it said that we haven't played winning teams," Johnson said after the Chiefs used two defensive touchdowns to beat the Buffalo Bills 23-13 on Sunday. We're the best you can be at 9-0 right now. If you can't respect it, then we're just going to keep winning. So far so good. Sean Smith scored on a 100-yard interception return and linebacker Tamba Hali produced the go-ahead points for Kansas City by returning a fumble 11 yards for a score. And now the Chiefs get to enjoy it for an extra week in entering their bye weekend off before returning to put their record to its biggest test on Nov. 17. That's when Kansas City travels to Denver for a highly anticipated AFC West showdown against Peyton Manning and the Broncos. "We have a bye coming up, a chance to kind of catch our breath a little bit," quarterback Alex Smith said. And then we'll start talking about the Broncos. The Chiefs keep winning despite a sputtering offense that managed just 210 yards and settled for three field goals. And their defense overcame its leakiest outing of the season after giving up 470 yards to a Bills offense that was led by undrafted rookie Jeff Tuel. What mattered was the final result, as the Chiefs matched their best start to a season, set in 2003, and extended their worst-to-first run after a 2-14 finish last year. The Bills (3-6) were left stunned in how they let this game slip away. Up 10-3 after the first half, they opened the second half by driving to the Chiefs 1, when Smith intercepted Tuel's pass and ran it the other way for a score. Obviously, it hurts. It hurts me. It hurts the guys in that room" Bills coach Doug Marrone said. I'm not going to stand here and say we should've won that game because we obviously didn't. But it hurt. Here's five things that made the difference as the Chiefs snapped a six-game losing streak at Orchard Park, dating to 1986. HAPPY RETURNS: The Chiefs' defense has scored six times this season. Smith's TD matched the second-longest interception return in team history, and he was too tired to enjoy it. Do you know how long 100 yards is? Smith said. I was definitely happy I made it. I wanted to celebrate, but I was so tired. Hali scored to put the Chiefs up 20-13 with 12:47 left. He scooped up a loose ball after cornerback Marcus Cooper punched the ball out of receiver T.J. Graham's hands. TUEL TIME: Tuel's first NFL start began well before faltering late. The undrafted rookie from Washington State got his first career touchdown - a 59-yard connection to fellow rookie Marquise Goodwin - as he finished the first quarter going 5 of 7 for 112 yards. Tuel struggled the rest of the way, going 13 of 32 for 117 yards with two interceptions. He started in place of interim starter Thad Lewis (bruised ribs) and with rookie starter EJ Manuel missing his fourth game with a sprained right knee. "Did Jeff play well enough for us to win?," Marrone asked. At times. At times he didn't. I think you could say that about a lot of people. ON THE RUN: Led by C.J. Spiller's 116 yards rushing, the Bills managed a season-best 241 yards against the NFL's 10th-best rushing defense. Spiller, who returned after missing one game with a sprained left ankle, had runs of 61 and 29 yards. He also caught two passes for 39 yards, giving him 155 yards from scrimmage. Chiefs running back Jamaal Charles had 90 yards rushing and only 6 receiving as he was held under 100 yards from scrimmage for the first time this season. STINGY D: The Chiefs matched an NFL record set by the 1977 Atlanta Falcons in allowing 17 points or fewer in nine straight games. The Chiefs have now allowed 111 points, their third-lowest total through their first nine games, according to STATS. Kansas City allowed only 88 points through nine games in 1969, and 101 points over that span in 1973. SACK-LESS: Kansas City was held without a sack for the first time this season, after managing a NFL-leading 36 through its first eight games. The Bills entered the game second in the NFL with 27 sacks. They managed just two against the Chiefs.