Kansas City, Mo. ? The Kansas City Chiefs looked as if they were two entirely different teams in their season opener.

The first three quarters, they looked like a team that might not win another game, blowing assignments and getting dominated at the line of scrimmage on both sides of the ball.

The final quarter, they looked as if they might not lose.

Ultimately, the Chiefs’ 33-27 overtime win over the San Diego Chargers was a microcosm of last season, when they started off 1-5 before rattling off 11 straight wins into the playoffs.

“I think every guy knows how bad we played, how poorly we played in the first half, and we’re not going to get away with it all the time,” Chiefs quarterback Alex Smith said.

“Some things in the second half went our way and we were able to get out of there with a ‘W,’ but as great as it is to win there’s going to be a lot to learn from, a lot to improve upon.

“You can’t start out that bad,” he said, “play that bad in the first half all the way around.”

Oh, but that second half.

The biggest comeback in Chiefs history began when Smith hit rookie Tyreek Hill with a touchdown pass to take a bite out of a 24-3 deficit. But it really hit its stride when the Chargers missed a 54-yard field goal early in the fourth quarter, giving Kansas City some desperately needed momentum.

Smith proceeded to lead his team to three straight scores, including a nifty 19-yard touchdown pass to Jeremy Maclin and Spencer Ware’s tying touchdown run with just over a minute to go.

In overtime, the Chiefs went 75 yards before Smith — checking out of the original play — kept the ball over the right side of the line and slipped through a crease into the end zone.

The danger in such a comeback victory is forgetting about what got the Chiefs into a 24-3 hole — glossing over the myriad problems that put their season opener in peril.

The Chiefs hardly touched Philip Rivers and didn’t sack him until late in the fourth quarter. The young defensive backfield was consequently shredded by a speedy wide receiver group, and Marcus Peters was beaten soundly by Keenan Allen before the wide receiver left with a knee injury.

Things were just as disjointed on the other side of the ball.

The Chiefs’ retooled offensive line allowed Smith to be sacked three times, and a group of wide receivers expected to be much improved was unable to get open against a suspect San Diego secondary.

“We knew we would have some learning to do with it being our first full game together. As a team, we came out a little rusty and we can’t do that,” tight end Travis Kelce said.

The Chiefs may have plenty to learn from their ugly start Sunday, but they at least can go to school with a 1-0 record. And ultimately, their ability to rally in the fourth quarter showed just how potent they can be once things start clicking.

“It’s one of 16,” coach Andy Reid said. “That first game can be overrated a little bit — there’s a lot of hype that goes into the first game of the season and there are 15 of them left. But I will tell you that (winning) doesn’t hurt you. For sure, it’s a good thing.”