Until their final drive on Sunday afternoon, the Eagles had managed just 10 points against the NFL's best defense and that wasn't going to get done. 

The Eagles got the ball back in the fourth quarter with 4:48 left in the game, down 15-10. They needed a touchdown and were given a nice gift when the Bears' punter shanked one that went just 36 yards. 

So the Eagles got the ball on their own 40-yard line. They needed to go 60 yards to take the lead and then hold on tight for the blocked field goal at the end. 

Here's how they were able to march down the field in a raucous stadium and take a lead on the NFL's best defense: 

This is the first-down play. The Eagles are in 11 personnel and Nelson Agholor went in motion from the right side of the field to overload the left side of the field. This is important because you'll notice that he gets picked up by linebacker Roquan Smith. Smith is an excellent player, but covering Agholor isn't really going to work. The deep safety will take notice. 

Since Agholor is streaking down the field against a linebacker, the safety takes a step in that direction as Alshon Jeffery is about to settle into a zone. 

Nick Foles does an excellent job of looking off Golden Tate, who was cutting inside. That freezes the cornerbacks.  

That little hesitation from the safety, who was watching Agholor, allows Foles to deliver the football in time to get a big gain of 15 yards to move the sticks. 

So after this play, the Eagles are at the Bears' 45-yard line. On the next two plays, they're going to get big contributions from Dallas Goedert and Agholor. 

We don't need to look at these plays too deeply, but just check out how both players fight for extra yardage. Every bit counts as they move down the field. 

Toughness on a beautifully designed misdirection screen play from Goedert after he made an impressive catch on a low-thrown ball. He bounces off a tackle and picks up the first down. 

And slick moves from Agholor and an 8-yard gain. This puts the Eagles on the Bears' 27-yard line with just over three minutes left. They're moving. 

The Eagles are in 12 personnel, which tells you how far Goedert has come this season. Foles makes this play. Goedert (circled) is about to go in motion and then run a little flat route. 

Foles uses his eyes to freeze the middle linebacker, Smith (circled in green). It looks like Foles is going to Goedert in the flat (he even uses a shoulder pump), which would have helped pick up the first down, but that look freezes Smith and Foles is going to throw over Smith in a tight window to Zach Ertz (circled) 

Check out the window Foles had to throw this into. There wasn't much there and Foles puts it where only Ertz could get it. 

The smallest details matter so much and this play happens really quickly. Foles basically just manipulates the young linebacker just enough to thread the needle with this pass and pick up a first down. 

This play gets the Eagles to the Bears' 14-yard line. 

This is a huge down. We'll get to the touchdown, but this was 3rd-and-9 from the Bears' 13-yard line. Without this conversion to Alshon, the touchdown might have never happened. 

A unique look out of the huddle, but Alshon is going to motion out of the backfield and the Eagles are going to find a way to manipulate this zone coverage. The key is the attention Zach Ertz warrants. 

Off the snap, linebacker Danny Trevathan has Jeffery, but Ertz is taking so much attention, that it's going to leave the middle of the field open. The secondary is in quarters, which means each of them is responsible for their quarter of the field. But the safety hesitates for just a second before driving toward Alshon because he had to respect Ertz so much. Ertz is just a decoy here. 

Trevathan has to leave Alshon to go with Sproles and Foles delivers a perfectly-timed ball to big No. 17 in stride. He was wild open. 

Big first down. 

Finally, here's the touchdown play on 4th-and-goal. Give credit to the Eagles for trusting Golden Tate and to Tate for being someone the Eagles could trust. Pretty simple design here that has been in the west coast offense forever. It's a sprint out that needs a perfect pass after Tate beats his man. 

This is what Foles was looking at just before he throws this ball. It's not an easy throw. It's on the run and he needed to change his arm angle. But Tate had apparently been dominating this route all week and he creates just enough separation on Sherrick McManis, whom the Eagles wanted to target on Sunday. 

Jeffery is the second option on this play, but this is really a play with one good option. That's Tate.

The key in this drive was timing and precise throws. Give Foles a ton of credit. He used his eyes to manipulate defenders on this drive and had to make throws in narrow window or at the exact right moment. Give credit to Pederson for understanding how much attention a guy like Ertz warrants from the opposition. And give credit to the O-line, because if they don't block well this whole drive, nothing else matters, does it? 

After this, the Eagles couldn't get into the end zone on the two-point conversion and it felt like Foles was going to leave the field with the lead and lose. But we know the rest of the story. That blocked field goal never happens without this clutch touchdown drive.