Although his team won last weekend, Claudio Bravo’s Manchester City debut against Manchester United was a disaster. Or at least it seemed that way.

Television pundits came out in full force, and they were led by former Arsenal striker Ian Wright: “He has to catch it or punch it, and doesn’t do either. The communication has to get better. For me, that is terrible.” It wasn’t just the analysts on TV taking issue with the Chilean keeper’s play. Bravo’s error was the most-tweeted-about incident yet in the new Premier League.

Except Bravo’s manager, Pep Guardiola, saw things differently. He was quick to commend his goalkeeper on his play with the ball, and he let the world know that Bravo had submitted “one of the best performances I’d ever seen.”

Of course, that’s hyperbole. Guardiola was defending a new signing who had displaced the English national team’s starting goalkeeper, Joe Hart, and had faced a storm of criticism after his debut mistake. Keepers are easy targets for experts and fans alike, and they’ll often go from an afterthought to Public Enemy No. 1 in the half second it takes to miscalculate a lofted free kick. But for Guardiola, shot-stopping and cross-claiming make up just a small portion of what a keeper does. They actually combine for a powerful tool: someone who can help move the ball out from the defense and ultimately create goals at the other end of the field.

For most teams, the goalkeeper saves shots, claims crosses, and does whatever else it takes to protect his goal. When his teammates have the ball, he disengages and anticipates any potential counterattacks. At only 29, Hart is still in his prime, and he did all those things over the past six seasons as City’s starter. So Guardiola ushered him out the door and allowed him to join Torino in Italy, on loan, replacing him with Bravo, whom City bought from Barcelona last month. The 33-year-old Bravo is the starter for the Chilean national team and had occupied the same role for the back-to-back Spanish champions over the past two years, but his CV is less important than what he’s able to do with his feet.

To implement his pass-first, possession-dominating style, Guardiola demands a strong passing ability from every player, including the goalkeeper. His Bayern team averaged 66 percent possession in the Bundesliga last year, and when you pair that with a well-coordinated pressing system that often wins the ball back as soon as the team loses it, the goalkeeper’s net is rarely tested. (Bayern conceded the fewest shots in Germany in each of Guardiola’s three seasons at the club.) It makes sense for the Guardiola keeper to be used in other ways; otherwise, for large parts of each game, he’d be no different from a spectator who’d wandered onto the field.

Related Arsenal Have an Arsène Wenger Problem

By the time Guardiola left Barcelona in 2012, goalkeeper Victor Valdes was a better passer than many of the world’s top-level outfield players. When Guardiola went to Munich, he gave Manuel Neuer a role that was revolutionary: The goalkeeper acted like a playmaker with gloves and would constantly venture out of his box to support attacking play.

As Valdes said in November 2011: “[Before Guardiola arrived,] I was not a goalkeeper that could see things tactically. I have improved tactically, and with my footwork …”

Valdes’s progress under Pep reached the point where he wasn’t fazed by, well, anything. After a misplaced pass gave Karim Benzema a goal 22 seconds into a Clasico of Pep’s final season, Valdes continued to coolly pass the ball in the same fashion, despite heavy pressure from some of the world’s best attackers.

Valdes, Neuer, and Bravo are all defined by their incredible composure.

The benefit of a keeper who’s comfortable on the ball is simple: He allows a team to possess the ball with 11 players instead of 10.

Guardiola places great importance on the build-up phase of possession, stating in a recent interview that “if you make a build-up, everything is easy.” By making short and accurate passes to move the ball up from the defense into midfield, Guardiola’s teams drag their opponents out of position, and that creates space higher up the field.

Of course this isn’t the same for all teams — a direct side, such as West Brom in England, or Eibar in Spain, is more reliant on what happens after the initial long ball. But for Guardiola, passing the ball from the defensive third up to the attacking third creates the foundation for their goals.

Against the man-to-man defenses that are common across the Premier League, the goalkeeper’s added role as quasi-outfield player adds a layer to this build-up play that becomes especially important. Although there were moments of uncertainty, Bravo played a crucial role in the build-up against United. His composure on the ball and capacity to engage in the building of plays allowed the visitors to resist United’s pressing and establish control: City had over 60 percent possession and doubled United’s number of shots on target.

In the derby, Bravo made 44 passes—bettering every United player other than Paul Pogba and Marouane Fellaini, who both equalled the City keeper’s tally. Plus, 15 of these were made from outside the safety of his box.

Bravo’s presence was crucial in helping to overload the United press. If United went man-to-man against City’s players, Bravo was the free player. And when Zlatan Ibrahimovic or Rooney moved up to close the keeper down, it meant that an outfield player would be free.

During build-up higher up the pitch, Bravo would move out of his box and take a position not far behind the center backs. From a more advanced area, the keeper helped City to switch the ball to the opposite side and escape United pressure.

City’s first goal against United came from a long ball from the back line. While Guardiola’s sides are hardly known for their direct play, the manager is aware that a long ball from a keeper can bypass an opponent’s press and exploit the space behind their defense. At Bayern, Neuer was able to drop the ball on the feet of a moving target.

Although it was a less-common tactic in Catalonia, Valdes could also ping an accurate long ball to release an attacker if an opposing press shut down his center backs.

Guardiola’s keepers need to provide some defensive cover — but they often do it outside of their own box and without their hands. Guardiola’s system is most vulnerable against counterattacks. As his teams push up and involve all the outfield players in the attack, there’s always plenty of open space behind the defenders. If the press doesn’t win the ball back, the keeper can help to cover any long balls over the top. Neuer became famous for this when playing for Germany.

With Neuer stopping similar transitions from a high position, Bayern had a greater freedom to stay in more advanced positions, and put more pressure on the opponent’s defense.

The use of a goalkeeper in build-up is an obviously risky tactic. It takes just one misplaced pass for the opposition to be gifted an automatic goal, and this could happen in two or three more Manchester City games this year.

Related A Manager Will Decide the Premier League This Season

The mistakes will probably be followed by a chorus of “Just boot it up the field!” However, there’s a calculus here: The few goals conceded from a keeper’s errors are worth all the extra possession and attacking fluency that comes from his involvement in build-up play. Without Bravo, more possessions would end up as aimless clearances up the field. Relinquishing possession to the opposition 20 more times per game means 20 more invitations for them to attack.

From a pure shot-stopping perspective, Bravo may have had a disappointing debut, but that neglects the majority of the work he did throughout the game. He might be City’s last line of defense, but he’s also their first line of attack.