Alex Smith fumbled the ball away three plays into the second half, then watched the Miami Dolphins turn that mistake into a touchdown.

He more than atoned for it, and the Kansas City Chiefs are winless no more.

Smith threw three touchdown passes, including one to running back Joe McKnight — who impacted a game for the first time since 2012 — midway through the third quarter to help snuff out a Miami rally, and the Chiefs topped the Dolphins 34-15 on Sunday.

McKnight had two touchdown catches for the Chiefs, who were outscored 50-27 in the season's first two games.

"Momentum's a funny thing," Smith said. "It's hard to put your finger on it, but certainly, this helps. This is what you're looking for, a win on the road, a tough win, I thought. I'm not sure what it is, but this is how you get started, for sure."

The Chiefs (1-2) were a minus-two in the turnover department, allowed Miami's Lamar Miller to rush for a career-best 108 yards, saw Smith get sacked five times — and still won, on the road, by 19 points.

That's how things are going right now for the Dolphins (1-2). They scored 23 points in the second half of Week 1 against New England — and have scored 25 points in the two full games that have followed.

"A hold here, a drop there, they are things that we are doing to ourselves that make things more difficult," Dolphins wide receiver Brian Hartline said. "But if you're playing the odds, eventually you can't overcome them all. So it gets tiresome and it kind of wears on you."

Knile Davis rushed for 132 yards and a touchdown for Kansas City.

Here's some things of note from the Chiefs' win:

TANNEHILL'S STRUGGLES: Even after Miami opened with a win against New England, the Dolphins said they knew the passing game had to get better. It hasn't. Dolphins QB Ryan Tannehill struggled for the third game in a row, this time against a pass defense ranked as the worst in the NFL. He went 21 for 43 for 205 yards.

DAVIS' WORKLOAD: Jamaal Charles is still out for Kansas City, but the running back corps delivered nonetheless. Davis got 32 carries for the Chiefs, his biggest workload since at least high school. Davis never got more than 30 carries in college — he had 30 on consecutive weeks for Arkansas in 2010 — and his NFL high before Sunday was a 27-carry day last season against San Diego. "We've got a good group," Smith said. "I think there was a reason we kept so many of them. I think you can see that now. They all have something to offer. "

MCKNIGHT'S CATCHES: McKnight tied a career-best with six catches, set a new career mark with 64 receiving yards and hauled in the first two TD grabs of his career. Before Sunday, McKnight's last catch was Nov. 18, 2012. He missed the 2013 season after being cut by the New York Jets, and hadn't recorded any stats this season coming into Week 3.

SUNSHINE STATE BLUES: Good thing for Florida State, or else the state of Florida would have had one doozy of a football weekend. Miami and Florida — along with the Seminoles, the other parts of the state's "Big 3" in the college ranks — both lost on Saturday, and No. 1 Florida State needed overtime to beat Clemson. And in the NFL, Miami, Jacksonville and Tampa Bay all lost, the second straight week that's happened. Maybe fortunately for Sunshine State fans, the Miami Heat open practice on Saturday.

MILLER'S DAY: Miller is the go-to back now for Miami, with Knowshon Moreno out for a few weeks because of an arm injury. Miller answered the call as well — his previous career-best was 105 yards, last Oct. 31 against Cincinnati.

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