KANSAS CITY, Mo. (AP) -- The best assist that Matt Ryan dished out Sunday wasn't one of the two touchdown throws to Julio Jones, or even his pass that found Tony Gonzalez for a third-quarter touchdown.
It was after Gonzalez had scored, when Ryan picked up a loose ball rolling around in the end zone. The Falcons quarterback ran over to Gonzalez, shoved it into his arms and told the longtime Chiefs tight end to celebrate, just like he did in the old days at Arrowhead Stadium.
Gonzalez took a couple steps, leaped and dunked it over the goal post.
The perfect celebration for the perfect season opener, as far as the Falcons were concerned.
Ryan passed for 299 yards, and even added a touchdown run to his three scores through the air, helping the Falcons whip Kansas City 40-24. Gonzalez had five catches for 53 yards as he began what is likely the final season of his sterling career in the place where it all began.
''It's been like a homecoming for me,'' Gonzalez said. ''There's nothing better than Chiefs fans. There are so many of them and so many diehards. It's a special feeling to come home like this.''
The reason Gonzalez ended up with Atlanta before the 2009 season is because the Chiefs were rebuilding and he wanted to play for a contender. He'd never won a playoff game in Kansas City, and still hasn't with the Falcons - so he's back for one more season in the trenches.
Gonzalez's touchdown catch in the third quarter gave Atlanta a 34-17 lead, part of a streak of 20 unanswered points that turned a close, offensive shootout into a rout.
''He's such a great part of this organization, you know, probably the greatest tight end to ever play the game. I think deep down in their hearts, Kansas City fans were happy to see that one more time,'' Ryan said, pausing. ''Maybe not at the time. Maybe in retrospect they will be.''
The Chiefs' Matt Cassel threw for 258 yards and had touchdowns running and throwing, but he also fumbled deep in Kansas City territory to set up a short TD, and his two interceptions created short fields that the Falcons turned into field goals by Matt Bryant.
Jamaal Charles had 87 yards rushing, and Tony Moeaki had three catches for 37 yards, both providing a bright spot for Kansas City. The pair of them, along with safety Eric Berry, played their first regular-season games since tearing their left ACLs last season.
Things weren't nearly as bright for the Chiefs defense, which had Pro Bowl linebacker Tamba Hali sitting out a one-game suspension for violating the league's substance-abuse policy.
Starting safety Kendrick Lewis (right shoulder), cornerback Brandon Flowers (right heel) and defensive tackle Anthony Toribio (right ankle) were inactive due to injuries, and that seemed like chum in the water to one of the league's top passing offenses.
''The season is a marathon, not a sprint,'' Chiefs coach Romeo Crennel said. ''We have at least 15 more to play, and we cannot let this game negatively affect the next 15.''
The next two are on the road: Buffalo and New Orleans.
''It's only one game in a long season,'' Cassel said. ''We obviously have to make a lot of corrections and get better as a football team. We've got to play collectively. We've got a lot of resilient guys in there. We're going to get back to work and get this thing fixed.''
The training staff may have as much to say as the coaches about that.
Without four starters on defense, Ryan spent Sunday picking apart what was one of the NFL's best defenses toward the end of last season. Both of his touchdown passes to Jones came before the half, and Bryant's two field goals helped stake Atlanta to a 20-17 lead.
Momentum finally shifted for good in the third quarter, when normally reliable Chiefs kicker Ryan Succop banged a 40-yard try off the upright.
Ryan led the Falcons on another touchdown drive, capping it with a 5-yard scramble, and then got the ball back moments later. Cassel was blindsided by John Abraham and the ball went squirting loose, and Stephen Nicholas pounced on it to give the Falcons the ball at the 7-yard line.
One play later, Gonzalez had a memorable homecoming touchdown.
''Tony Gonzalez, without a doubt, is going to be a first ballot Hall of Famer,'' Falcons coach Mike Smith said. ''We knew it was going to be an emotional week for him.''
As for his signature dunk, well, Gonzalez nearly didn't do it.
''But Matt put the ball in my chest and told me to go dunk it,'' he said. ''I heard the boos that were coming with it. But I want the fans to know it wasn't a disrespect thing. That's me, that's how I made my bones coming up in this league.''
NOTES: There was no controversy with the replacement officials. Both times that referee Mike Shepherd reviewed a call, the original decision stood. ... Atlanta CB Brent Grimes left in the fourth quarter with a calf injury. ... Nicholas finished with a game-high 12 tackles, recovered a fumble, picked off a pass and had two pass deflections. ... Bryant was 4 for 4 on FGs.
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