When you have problems on the defensive side of the ball, it leaves you with a razor-thin margin for error on the offensive side.

There has probably never been a better example of this than the 29-28 Atlanta Falcons loss to the Kansas City Chiefs.

The game really turned on two plays, both on interceptions made by safety Eric Berry. The first was a 37-yard pick-six at the end of the first half which gave the Chiefs a 20-13 lead—one they didn’t relinquish until the Falcons scored with 4:37 left in the game.

The Falcons decided to go for a two-point conversion—a logical decision since an extra point still left them vulnerable to losing if the Chiefs kicked a field goal and the Falcons defense hadn’t been able to slow the Chiefs offense down in critical moments.

And that’s when the second interception happened, although since it was during a two-point conversion attempt it isn’t logged on quarterback Matt Ryan’s stat sheet.

Do the Falcons push for that two-point conversion if their defense was a unit the team could trust?

Coming into the game, the Falcons were the No. 27 defense in the league, statistically speaking, ranked last against the pass (averaging 282.2 net passing yards per game, with 25 passing touchdowns) and middle of the road against the run (averaging 100.8 yards a game and allowing 11 touchdowns).

It’s a bad defense, and the Falcons have been winning by out-shooting their opponents. Their wins have mostly been about exhausting the opposing defense by scoring early and often, while also exhausting the opposing offense as it tries to keep up.

The problem was—and this is not the first example of it, just perhaps the best—if the offense struggled, the defense couldn’t carry the team. So if the Falcons offense doesn’t score, most of the time they lose.

In Atlanta’s seven wins, the offense has averaged 37.8 points a game. The only time they scored less than 30 points in a win was against the Denver Broncos when they scored 23. In losses, the Falcons scored an average of 24.2 points a game, the only outlier 33-30 loss to the San Diego Chargers.

Even accounting for the three defensive scores (there are no scores by the special teams this year), that’s a pretty significant difference and when the defense allows an average of 27.6 points per game (fourth-worst in the NFL), the difference can be too much to overcome.

So when a quarterback makes two mistakes in an otherwise good game, it’s too much to overcome because it makes a bad defense have to work harder.

While in reality it’s very rare than one or two things cause a loss—it’s usually a myriad of events—and we have seen other examples of the Falcons suffering because of their defense (a 24-15 loss to the Eagles), never has it been so starkly shown what little margin for error the Falcons have left themselves.

It’s easy to blame Ryan for this loss, as he handed the Chiefs two scores. However, a better defense might have given the Falcons more room for mistakes from the offense.

And when it comes to the playoffs, that margin for error will become even slimmer.