KANSAS CITY, Mo. -- Andy Reid joked this week that some plays the Kansas City Chiefs unveil during games look like they were just drawn up on the sideline.

The so-called "Hill Mary" on which the Chiefs scored a touchdown on the final play of the first half in their most recent game against the Dallas Cowboys was not one of them.

"That's one we work on every week," Reid said. "That's been one that we've had in a long time."

With the Chiefs at their 44 and many of the Dallas defenders backed up deep and guarding the end zone, quarterback Alex Smith threw a short pass to the uncovered Tyreek Hill, who made the catch at the Dallas 42.

The Chiefs' Tyreek Hill scored an improbable touchdown with a 56-yard catch-and-run on the final play of the first half against Dallas. AP Photo/Michael Ainsworth

Between some nifty running by the receiver and downfield blocks by wide receiver Demarcus Robinson and tight ends Travis Kelce and Demetrius Harris, Hill found his way into the end zone.

A touchdown might seem like an unlikely result of the play. But it worked much like it does on the practice field when the Chiefs run through some unusual game situations they might eventually confront.

"It's something we've been practicing all year," Hill said. "We did a great job of executing, blocking down the field. Starting with Demarcus, Travis, Demetrius, all those guys did a good job giving me a lane. I just used my speed [and] it turned out amazing.

"It's just a feel thing. I'm a punt returner. I guess it was set up like a punt return. So I just used my instincts."

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Hill's speed, instincts and ability to run in the open field made him the obvious choice as the receiver. First the Chiefs had to arrive at the playcall.

For that, they had some options. They were at their 44 with two seconds left in the half, making the situation touchdown or bust.

A Hail Mary, perhaps the traditional playcall in such a situation, was an option.

"There are so many different situations at the end of half and end of game depending on how they play you and time on the clock," Smith said. "So I felt good about taking a shot as opposed to throwing up a Hail Mary there."

That's because of how the Cowboys were aligned before the snap. They had seven defenders inside their 10-yard line, making the Hail Mary seem like a low-percentage choice.

With the Hail Mary seeming the most likely option for the Chiefs, they anticipated how the Cowboys might align themselves.

"We somewhat predicted what we thought they would do," offensive coordinator Matt Nagy said. "It's hard to say exactly where they're going to put those eight other guys. Most teams do usually rush three and drop everybody else. They did that. They put everybody really deep and we just took advantage of it.

"We have a few different things we can do on that. That play there, it ended up being the right one."