If there were lingering doubts over who Barcelona’s most important player is, the 3-1 defeat by Borussia Dortmund in their Champions League quarter-final second leg provided an emphatic answer.

Without the rested Pedri in the starting line-up, Barcelona put in arguably their worst 59 minutes of the season. Dortmund could even have won the tie but they spurned multiple chances.

Barcelona’s out-of-possession game struggled with Ronald Araujo and Gerard Martin — replacing Inigo Martinez and the injured Alejandro Balde, respectively — unable to hold Hansi Flick’s high line. But Barcelona needed controlled spells of possession in the face of pressure to kill this tie and found little of it in Pedri’s absence.

The first minute of the game in Germany provided evidence of how Dortmund’s pressing could create issues for Barcelona.

Dortmund manager Niko Kovac ditched the 4-5-1 shape from the 4-0 first-leg loss for a 3-4-3 system, with central midfielders Felix Nmecha and Pascal Gross monitoring Frenkie de Jong, as seen below.

Araujo passes across the box to Pau Cubarsi, triggering the Dortmund press. As Cubarsi returns the pass, Gavi drops to help De Jong. Nmecha switches to marking him while Serhou Guirassy now helps Gross cut out the pass to De Jong.

A couple of passes later, Dortmund shift to the right to hem Barcelona in, which frees De Jong. But Araujo, who is limited on the ball, passes to right-back Jules Kounde, and he is immediately pressured.

When the same opportunity presented itself in the 17th minute after Guirassy’s opener, Araujo passed to De Jong instead. The issue for Barcelona here — and throughout the first half — is the distance between De Jong and his naturally attack-minded midfield partners, Gavi and Fermin Lopez…

De Jong goes back to Cubarsi, who finds Martin. That prompts Dortmund wing-back Yan Couto to push up, leaving Raphinha in space. Flick points and Martin passes to the Brazilian, whose switch to Lamine Yamal is too heavy.

Dortmund reacted to that Barcelona strategy by pushing Couto all the way up to their opposition’s defensive third, resulting in errant long passes from Martin. Barcelona returned to trying to progress the ball through the middle and faced the same issues.

In the 33rd minute, Cubarsi receives a pass with Guirassy moving towards him. The Spaniard, renowned for his line-breaking passes when played on the right (but in this game operating on the left), goes back to Wojciech Szczesny, who passes to Araujo.

With a Dortmund player closing Araujo down, a first-time pass to De Jong would have given Barcelona space to progress, particularly with Gavi dropping to support.

Instead, Araujo takes a touch, inviting pressure before playing the safe pass to Kounde again, limiting Barcelona’s avenues for progression.

The move, apart from outlining the magnitude of Martinez’s absence, is an indication of why De Jong was never viewed as Sergio Busquets’ natural successor. The Netherlands international plays his best football when another midfielder operates close to him, freeing him up to carry the ball forward. But those opportunities were limited in the first half of this game.

In the 37th minute, Fermin, Gavi and De Jong are positioned together — a rare occurrence — and pass between each other just ahead of the halfway line.

But as De Jong receives and checks his options, Fermin and Gavi both move forward, and two Dortmund players are now free to press him. De Jong is also not helped by Raphinha and Robert Lewandowski being in offside positions.

De Jong passes back to Cubarsi before turning around to express his displeasure.

Dortmund going 2-0 up on the night saw Barcelona finally chain some moves together, resulting in a 54th-minute Ramy Bensebaini own goal.

Pedri’s arrival off the bench five minutes later ensured that the game did not turn into a basketball affair. In just six minutes, he provided everything Barcelona had missed in the first hour.

Within a minute of coming on, the Spaniard had an impact. As Lopez finds De Jong with Dortmund trying to compress space, Pedri escapes his marker.

De Jong passes to Kounde, who finds Pedri in space.

The pass is slightly ahead of him, but Pedri stretches to find Lewandowski, giving Barcelona’s forwards their first three-on-three situation.

Three minutes later, it happens again.

Pedri once again finds space and is found by Kounde from a De Jong pass. He then spins away from pressure to pass to Martin in space.

Barcelona’s best move of the second half owed plenty to Pedri too. His positioning below allows him to receive a pass from Cubarsi…

Pedri passes back to De Jong and runs towards him instead of turning and moving ahead.

The run drags two Dortmund players towards him. Pedri operating close to De Jong creates space for the latter to carry the ball forward into the midfield gap.

De Jong passes wide to Martin, whose cutback reaches Lopez thanks to Raphinha’s dummy. Lopez takes a touch to settle himself, but shoots over.

A minute later, Pedri showed how he might have helped Barcelona counter Dortmund’s press, which had understandably suffered a drop in intensity.

He controls a hacked aerial clearance from Araujo under pressure before passing back to Cubarsi, who in turn passes to Martin as Pedri runs towards the left-back.

That triggers two Dortmund players to step up towards Pedri, as they did in the first half with De Jong, while a third attempts to cut out a backpass. But Pedri’s move creates space for Martin to switch the ball to the other side, extending Barcelona’s time on the ball.

That six-minute spell was crucial to Barcelona avoiding a debacle similar to the ones they suffered against Roma in 2018 and Liverpool in 2019; games where they required controlled possession that broke through the opposition press but could not generate it.

Pedri’s clarity in thought with and without the ball made the difference despite the late Guirassy goal that led to a nervy finish.

Barcelona’s possible semi-final opponents, Inter or Bayern Munich, pose similar, if not more daunting, questions with their pressing. Beating either team will hinge on their 22-year-old midfield general gliding past and passing through it all.