When a team blows a 21-0 lead like the Rams did Sunday in their 34-31 loss to the Cowboys, there’s always plenty of blame to go around.

For starters, give Dallas credit for sticking with the run despite facing that early deficit. It could have been easy for Jason Garrett and Co. to throw out their game plan at that point and compound the issue by being one-dimensional. Instead, following Janoris Jenkins’ 25-yard pick-six to give the Rams a three-touchdown lead, the Cowboys went on an eight-play, 80-yard drive that consisted of DeMarco Murray doing whatever he wanted to the Rams’ defense. As it turned out, that drive was one of the turning points in the game.

Despite not practicing during the week, Tony Romo’s back looked fine when he found Dez Bryant wide open on a 68-yard touchdown right after halftime to cut the Rams’ lead to 21-17. Jenkins was supposed to be man-to-man with Bryant the entire game, and until that point, he had more than held his own while facing the Cowboys’ best receiver. But thinking he was supposed to pass Bryant off to safety Rodney McLeod, he came off Bryant and jumped a crossing pattern, which is exactly what McLeod did as well. The end result was Bryant catching a touchdown pass from Romo, who said following the game that that was the most wide open he’d ever seen a receiver.

From Bruce Carter’s pick-six to Jared Cook’s drop in the end zone that would have given the Rams a 28-0 lead, there were other moments of missed opportunities or crucial mistakes that plagued the Rams throughout the day. A botched Scott Wells snap and two horrendous penalties called on Eugene Sims didn’t help matters, either.

But considering the Rams held a 21-0 lead and scored 31 points on the afternoon, this loss falls on the defense and, by extension, the coaching staff. All offseason, the talk was about how the Rams just needed to get to the fourth quarter with a lead and the defense would take over from there. Instead, the run defense has been an issue since preseason, and the team has just one sack in three games. The identity of this team is its front four, and yet that unit has also contributed to many of the Rams’ problems through three games.

Below are three plays that defined the Rams’ 34-31 loss to the Cowboys. As I’ve highlighted, there were huge plays throughout the course of the game that contributed to the loss. But in sticking with the theme, all three of the plays below were part of a series in which the defense couldn’t generate a stop despite the team clinging to a four-point lead early in the fourth quarter.

PLAY 1: The Romo Scramble.

Cook drops an easy touchdown pass that would have extended the Rams’ lead early in the fourth quarter to 28-20. Instead, the Rams settle for a field goal, and their defense is tasked with stopping a Dallas offense that has scored on both of its second-half possessions.

Following an illegal blocking penalty on tight end Jason Witten, a 1-yard Murray run, and a 3-yard reception to Bryant, the Cowboys faced a third-and-13 from their own 13-yard line. Dallas comes out in an empty back, 3×2 spread formation with three receivers to the play side and two to the boundary. From a coverage standpoint, the Rams play it perfectly. On the boundary side, Jenkins reads the No. 1 receiver and covers his outside area while McLeod reads the No. 2 receiver and covers the inside area. On the three-wide side, E.J. Gaines stays outside on the No. 1 receiver while T.J. McDonald stays over the No. 2 receiver, and James Laurinaitis and Lamarcus Joyner stay underneath that same receiver, who runs a fly route.

The problem occurs when Kendall Langford drops into coverage to trail Witten, who is the inside receiver on the three-wide side. As Witten takes off up the seam, Langford follows him, allowing left guard Ronald Leary and center Travis Frederick to double-team Michael Brockers at the snap. Right guard Zack Martin is also free to help right tackle Doug Free double-team William Hayes, and while Robert Quinn beats Tyron Smith to the outside and forces Romo to step up into the pocket, it also creates a domino effect that favors the Cowboys and causes the entire play to break down for the Rams.

Initially Romo tries to escape to the outside where Quinn just vacated, but Brockers does a good job mirroring Romo and quickly cuts off his path. This causes Romo to cut back inside, where there’s nothing but green grass in front of him because Langford is up the field in coverage.

Realizing that Romo has broken the pocket, Alec Ogletree runs up to make the tackle. But Romo somehow jukes Ogletree and runs an additional five yards before falling down at the 29-yard-line, where he’s touched down by Joyner. The end result is a 16-yard gain for Romo and a first down for the Cowboys to keep the drive alive.

PLAY 2: Williams Finds a Soft Spot.

On that same drive, the Rams once again do a great job on first and second down to force a third-and-14 at the Dallas 25-yard-line. This time the Cowboys line up in a 3×1 formation with three receivers (which includes Witten detached from the line) to the play side, while Bryant matches up one-on-one with Jenkins to the boundary. Murray is the lone back with Romo, who lines up in shotgun.

At the snap, McLeod and Joyner blitz from opposite edges while Laurinaitis and Ogletree drop into coverage. Jenkins stays with Bryant while Gaines covers his quarter and Cody Davis flows over the top to help combine with Gaines to cover Gavin Escobar, who runs a fly route. McDonald, who walked down on Escobar at the snap to help cover for the blitzing Joyner, drops into coverage.

That’s where the play breaks down on multiple fronts. While keeping his eyes on Romo, McDonald thinks that Romo wants to throw outside the numbers, so he breaks for the sideline. But just as he does that, Terrence Williams cuts inside and finds a soft spot in the zone over the middle of the field.

Why wasn’t anyone underneath? After Laurinaitis shows blitz and then drops into coverage, his eyes go to Romo, whose first read was to Bryant on the right side of the formation. Laurinaitis bites on Romo’s pump fake, and by the time he gets back to the play side where Williams is, Romo has already slid in the pocket to open up a perfect passing lane to hit Williams for a first down.

If McDonald doesn’t break outside, he probably has a play on the ball. If Laurinaitis doesn’t bite on the pump fake, then maybe he gets enough depth in coverage to force Romo to either hold onto the ball or throw it into double coverage. If Romo doesn’t fake and tries to force the ball to Bryant, then Laurinaitis might be in perfect position to intercept the pass underneath.

Either way, the end result was a 20-yard completion to Williams and another first down to keep the drive alive.

PLAY 3: Cowboys Take First and Last Lead.

On that same drive, a pass interference call on Jenkins sets the Cowboys up with a first-and-10 at the Rams’ 20-yard-line. Following a Murray 3-yard run on first down and a five-yard reception on second down, the Cowboys face a third-and-2 from the Rams’ 12-yard line.

On third down, Romo lines up in shotgun and is flanked by Witten and Murray. He has two receivers to the play side, and Bryant once again lines up as the lone receiver to the right against Jenkins to the boundary. Witten then goes in motion, and the Rams tip their hand as Ogletree follows Witten into the slot.

Romo now knows the Rams are in man-to-man coverage with safety help over the top of both Bryant and the three receivers to the play side. At the snap, Williams (the outside receiver on the play side) runs a quick slant underneath Cole Beasley (the middle receiver on that side) and Witten. Gaines, who can’t navigate through the traffic in order to cut him off, helplessly watches as Williams catches an easy touchdown pass over the middle. There’s nothing Gaines or any of the Rams’ defenders can do on that play.

These three plays are just some of the chess matches that can make or break teams on Sunday. The Cowboys dialed up the right play calls at the exact right times, and it led to the Rams’ demise.