It’s a victory 21 years in the making.

For the first time since 1999, Galatasaray beat their crosstown rivals Fenerbahçe in Kadıköy, Istanbul. The reigning Süper Lig champions defeated their eternal enemies by a score of 3-1. Goals from Ryan Donk, Radamel Falcao and Henry Onyekuru sealed the deal for the visitors, who came back from 1-0 down to clinch the victory.

Both teams ended the match down a man — Galatasaray’s Younes Belhanda was sent off in the 84th minute for a double yellow, and Fenerbahçe’s Deniz Türüç received a red card for violent conduct as well.

The win puts Galatasaray within a point of current league leaders and fellow Istanbul-based club İstanbul Başakşehir. It also pushes Fenerbahçe down to sixth in the table, eight points away from first place and outside of a European spot. It all but confirms their sixth straight season without a league title.

Galatasaray have won at Fenerbahce for the first time since 1999 😲 Galatasaray won 3-1 but Fenerbahce coach Ersun Yanal, Galatasaray's Younes Belhanda and Fener's Deniz Turuc were all sent off during the second half 🤯 pic.twitter.com/RWXfYLxWK6 — Goal (@goal) February 23, 2020

But rather than celebrate a historic victory, Galatasaray almost let the result slip out of their hands.

In the 89th minute, with both teams playing down a man, Fenerbahçe won a free kick about 35 or so yards away from Galatasaray’s goal. Mehmet Ekici, who was only just subbed on, stood over the free kick. Despite its distance away from the goal, the German-born Turkish international elected to shoot. He struck the shot sweetly and curled it to the left side of Galatasaray’s goal. For a brief moment, an equalizer looked to be on the horizon.

And if not for Fernando Muslera, the shot would’ve reached its intended target.

The Galatasaray goalkeeper was enjoying a relatively quiet game. He had only faced two other shots up until that point — one from the penalty spot, which he conceded, and one from open play, which he stopped.

But his club needed him at this point, and the Uruguayan — who captains Galatasaray — refused to let his side down. He hopped to his left before pushing off of the ground, extending into a one-handed diving motion. Muslera got just enough lift-off to reach the shot in time and he used his left palm to divert the free kick around the post.

This went under the radar yesterday: a great save from Fernando Muslera in the 88th minute whilst his Galatasaray side were leading 2-1 against Fenerbahçe.pic.twitter.com/k9m9X9hddT — Karan Tejwani (@karan_tejwani26) February 24, 2020

The save was colossal in securing the victory. It prevented Fenerbahçe from tying the game at the death, and it set the stage for Onyekuru’s insurance goal in added time.

Had Muslera not made the save, Galatasaray’s Kadıköy curse likely would’ve been extended.

Muslera’s save did not go unnoticed — social media quickly lit up with praise of the Uruguayan’s stop.

Fernando Muslera, senin Galatasaray’a geldiğin güne şükürler olsun be adam.. — Pops Emre-Bonsu 🔥 (@EmreErgenekon) February 23, 2020

muslera o frikiği nasıl çıkardın aq… adam düz penaltı hariç gol yeme işini kesti, büyük konfor — mehmet margosyan (@kofiakofo) February 23, 2020

2011 Temmuz'da Türkiye Süper ligine geldi ve hiçbir şey eskisi gibi olmadı… Fernando Muslera! pic.twitter.com/ieLwcl6YpB — Galatasaray (@RTGalatasaray) February 24, 2020

And why wouldn’t viewers praise him? The stop was a fantastic denial of a dead-ball effort that had a legitimate shot at finding the back of the net. Muslera really had to track the ball well, and he timed his dive to perfection.

Let’s also not forget about the circumstances surrounding the save. Muslera’s stop preserved a tight lead (2-1) in a monumental moment (89th minute) of an emotionally-charged match (derby between Turkey’s top two historic clubs) in a setting which had been unkind to Galatasaray before (the Yellow-Reds had not won in their last 23 visits to the Şükrü Saracoğlu Stadium).

This save could go down as one of the top stops in Galatasaray’s history, especially if they go on to retain the league title. And I’m not saying this as hyperbole.

But for all of the plaudits, there is a part of this save that has been rarely mentioned. It’s a very underappreciated but important part of the stop, and without it, it’s possible Muslera would not have stopped this shot at all.

I’m talking about Muslera’s decision to go with a one-man wall.

At first, a one-man wall seems detrimental to a goalkeeper’s goals. If you want to increase your chances of blocking a shot, why not put more bodies into the wall?

And, in some scenarios, you would be right. In certain cases and areas, such as directly around the 18-yard box, bulking the wall up with players would make life difficult for a shooter due to the ball’s proximity to the goal. The shooter would find it challenging to work the ball around the wall while keeping it on target.

But from a great distance similar to the one Ekici took his free kick from, where there’s enough distance between the ball and the goal for a shot to dip, swerve and move, more bodies would actually do more harm than good for a goalkeeper. Bulking up the wall would manipulate the goalkeeper’s starting position in a negative way, give the shooter a clear area of the goal to aim at, and most importantly, obstruct the goalkeeper’s sight of the ball.

Let’s take a look at the below screenshot.

Notice where Muslera is positioned. He is standing near the centre of his goal. This is important because it gives him the best chance of reacting to a shot going to either side of his goal. If Ekici strikes the ball to Muslera’s left, he’ll be able to react in time. And if Ekici strikes the ball to Muslera’s right, he’ll also be able to react in time.

Had Muslera’s teammates formed a bulkier wall, the goalkeeper would’ve had to position himself closer to one of his posts to get a clear view of the ball. This, in turn, would’ve committed him to one side of the goal while leaving the other side of the goal heavily exposed to a shot that’s likely to dip over or curl around his wall.

By limiting his wall to just a single body and positioning himself in the centre of his goal, Muslera is also taking an advantage away from Ekici. Free kick shooters tend to use the wall as a reference point for their shot. Because the wall influences a goalkeeper’s starting position and thus exposes a side of their goal, it allows the shooter to zone in on that specific part of the goal and mould their shot based on that target.

But Ekici doesn’t have that luxury in this scenario. Muslera’s one-man wall is not a big enough reference point for Ekici to use. Muslera is also positioned in the centre of the goal, so there’s no significant side of the goal that gives Ekici a higher chance of scoring than the opposite side.

Most importantly, a one-man wall gives Muslera a clear view of the free kick. One of the most important things for a goalkeeper, especially when it comes to dead-ball situations, is there ability to see the shot. The clearer the view a goalkeeper has of an attempt, the likelier they are to actually stoping it. Take the goalkeeper’s sight of the ball away and you obstruct the goalkeeper’s ability to react to the shot in time.

Here, a bulkier wall would’ve obstructed Muslera’s view of the free kick’s position, Ekici’s position and runup, and the shot’s entire flight.

But, by limiting the wall to just one man, Muslera is able to get a good read of the entire situation. He knows exactly where the ball is placed, how Ekici is running up to the ball, and which side of his goal the shot is travelling too. This also means Muslera sees the ball throughout its flight, allowing him to set himself appropriately and react accordingly.

And it’s great that he saw all of that too because Muslera almost got caught cheating. If you watch the save back, you’ll notice that the Uruguayan takes a step towards his right side as Ekici approaches the ball, Muslera is initially cheating to his right side because he thinks Ekici will strike the ball to that side of the goal. It wasn’t until after Ekici struck the ball that Muslera, reading the shot’s movement to his left, resets himself and reacts to his left side.

Had Muslera set up a busier wall, he would’ve seen the attempt late & not have been able to reset in time. As a result, we’d be talking about an entirely different outcome

To really drive the point home, let’s look at a goalkeeper who used a bulkier wall in a similar situation and was punished for it — Colombia’s David Ospina during the 2014 FIFA World Cup.

This free kick was taken from about the same distance as Ekici’s free kick but instead of using a one-man wall like Muslera, Ospina opted for a four-man wall.

Unfortunately, this resulted in Ospina’s vision being severely obstructed. Although Ospina is positioned near the centre of his goal, he’s forced to look through the spaces between his wall to catch glimpses of the free kick. He does not have a clear sight of the ball, nor does he have a clear sight of who’s taking it. Both David Luiz and Hulk are standing over the ball at different angles, and because Ospina’s vision is obstructed, he can’t tell who is approaching the ball and thus set himself appropriately.

As a result, Ospina doesn’t react until the shot is about halfway between David Luiz and Ospina’s goal, and due to the strike’s incredible power and movement, Ospina cannot react in time. The ball strikes the netting behind Ospina and Colombia are eliminated from the tournament.

Had Ospina set up a one-man wall, he would’ve seen the ball throughout the entirety of its flight and he would’ve had a better chance at stopping it.

Fortunately for Galatasaray, Muslera was smart when setting up his wall. By sticking with a one-man wall, Muslera was able to take a central starting position and give himself an equal chance at stopping a shot going to any side. He also took away a significant reference point for Ekici, who couldn’t use the wall to mould his shot anymore. Finally, he had a clear sight of the shooter’s runup and the ball’s flight, from the moment Ekici struck it to the moment Muslera directed it away. This was his saving grace, as it allowed him to right his wrong of cheating as quickly as possible.

All of this led to an excellent diving save from the Uruguayan, who cemented his place in the Galatasaray history books through the resulting victory.