In the Zone: Porto 1-0 Arsenal performance analysis

Arsenal had scored 11 goals in their two previous away fixtures before arriving at the Estádio do Dragão yet they failed to produce a single shot on target before succumbing to Galeno's goal in added time.

In this article brought to you by FedEx, the UEFA analysis unit, working with the match observer at the Dragão, shine a light on the key features of this narrow UEFA Champions League last-16 first-leg victory for Sérgio Conceição's side.

Team formations

Features

Arsenal's positional play

Mikel Arteta's men had a large share of possession (64%) but struggled to create any serious danger with none of their seven goal attempts ending on target. "We lacked threat, we lacked aggression especially when we had the ball in the final third," said Arteta afterwards, citing the need for greater purpose.

The video above looks at Arsenal's work on the ball on a frustrating evening. They looked to find space with movement in behind, as noted by the match observer who said: "Arsenal were waiting to penetrate in behind the back four with deep runs."

The first clip shows this and other features of the north London side's approach play. Their shape morphs into a 3-2-5 in the build-up with right-back Ben White moving inside alongside Declan Rice. Ahead of them, they have a front five which includes all of Martin Ødegaard, Kai Havertz and Leandro Trossard as No10s working between the lines.

As this sequence displays, it was difficult to find space with Porto packing the central areas with bodies, and the action ends with Pepe – who, at 40 years and 360 days, made history as the oldest starter in a Champions League knockout tie – showing his enduring defensive qualities to win the ball before Arsenal commit a foul.

To seek space, Arsenal's players kept interchanging positions. In the second clip Ødegaard drops back towards the halfway line, on the right, into a 'false full-back' position. The heat map shows the different positions he took up, including in central midfield. This illustrates the flexibility of an Arsenal team who interchange frequently within their structure – and the forward run that follows from White underlines the point.

For all that movement, Arsenal struggled to find gaps in the Porto defence as seen in the third clip too. Here Havertz's movement creates space in between the lines for Ødegaard, who is able to feed Bukayo Saka on the right. However, with Porto defending their box with seven men, no cross comes in and Arsenal end up going backwards.

Porto's defensive organisation

Porto kept just a single clean sheet in the group stage but they have found their defensive groove since then and this was their sixth consecutive shutout at home. They achieved it with a display marked by discipline and hard work.

As coach Sérgio Conceição said: "We were very good on a tactical level. The players understood the game plan. Their wingers [Gabriel] Martinelli and Saka are very fast and Ødegaard and Havertz inside are very tough to block. We did very well, we controlled them going deep and also the [attempts to] play inside."

The first clip above shows how they protected the space centrally, pushing Arsenal backwards. From a tactical perspective, the key point here is how, in a 4-1-4-1 defensive shape, each winger is working together with the midfield player behind them to protect the pockets of space. On the right, Pepê and Francisco Conceição work in tandem, as Nico González and Galeno do the same on the left.

"They showed excellent intensity and body positioning, blocking any internal balls and keeping good distances," said the UEFA observer.

The second clip shows Arsenal attempt to progress the ball up the field with Porto protecting the central areas once more. Galeno, the eventual match winner, is highlighted for his defensive work and the sequence ends with Ødegaard attempting a long crossfield pass – a response to the challenge of finding space centrally.

To highlight Arsenal's frustrations, between the 53rd minute and added time, they did not manage a single shot. "In the second half the biggest impact on the game was from Porto's defensive structure and organisation rather than Arsenal's play on the ball," said the match observer.

Porto's desire to keep Arsenal out was also reflected by the fact they won 54% of their duels – a success rate only bettered by Inter (64%) among the teams in action in this week's last-16 ties.

Porto in possession

Amid their impressive defensive efforts, Porto also produced the only two attempts on goal of Wednesday's first leg. This was a product of their directness when they attacked, looking for 1v1s in the wide areas, especially on the right.

The first clip above shows the build-up to Galeno's near miss in the first half and it begins with them building from their own goal, playing through Arsenal by creating an overload on the right and then progressing via their diamond shape in the middle.

In the second clip we see an example of their work down the right wing where full-back João Mário and winger Francisco Conceição asked questions of Jakub Kiwior, the Arsenal left-back.

When the opportunity arose the home team were able to get players forward quickly and benefitted from the 1v1 threat of their attacking players – as seen in the final clip with the fast feet of Francisco Conceição.

Lessons for player development

"These analysis articles form part of a strategy of translating findings from our senior club and national team competitions into actionable insights for elite youth development. By looking at trends from the Champions League, men's and women's, these articles can be used as an engine for player development across the European landscape."
UEFA's Head of Technical Education & Development, Olivier Doglia