Alonso’s debut win in jeopardy as Real Madrid accused of rule breach over new signing

Robin Bairner
Robin Bairner
  • 20 Aug 2025 08:42 BST
  • 4 min read
Franco Mastantuono, Real Madrid, 2025/26
© IMAGO

Real Madrid face the prospect of having their 1-0 La Liga win over Osasuna on Tuesday overturned due to the “improper alignment” of one of their new signings.

Article continues under the video

A Kylian Mbappe penalty, itself controversially awarded, was sufficient to give Xabi Alonso a winning start on the field in the league, but the victory could be overturned as controversy rages over the presence of Franco Mastantuono.

Real Madrid signed the 18-year-old Argentine from River Plate in a deal that went through earlier in August for an initial €45 million.

Current ETV
Player image Franco Mastantuono
Franco Mastantuono

F (R)

Real Madrid logo

Real Madrid

Franco Mastantuono
Franco Mastantuono

F (R)

Real Madrid

Real Madrid

€34M

ETV Range

€30.6M - €37.4M

The teenager made his competitive bow for the club after 65 minutes at the Bernabeu in a decision that could cost Los Blancos the win.

Miguel Galan, lawyer and president of the National Centre for the Training of Football Coaches (CENAFE), believes Real Madrid were guilty of an "incorrect line-up" by fielding Mastantuono.

What’s the issue with Real Madrid playing Mastantuono?

Mastantuono played in the No.30 shirt, which is put aside for reserve players.

Although the Argentine explain in his press conference is due to personal reasons, yet Trent Alexander-Arnold’s favoured jersey at Liverpool was No.66, which he has had to put aside to wear No.12 at Real Madrid.

It is claimed that as there is no legitimate reason for doing this, Real Madrid have committed an offence.

Furthermore, if Mastantuono is registered as a reserve player, which would allow Los Blancos to free up a spot in their squad and give them Financial Fair Play (FFP) advantages, this could also backfire.

Galan points out: “As long as player Mastantuono doesn't train or participate in matches with the reserve team, there is a substantial risk that his lineup will be challenged should he participate in official matches, due to a possible violation of the regulations regarding improper lineup.”

Franco Mastantuono, Real Madrid, 2025/26
© IMAGO - Franco Mastantuono, Real Madrid, 2025/26

What happens now?

Osasuna have 24 hours to point out the alleged rule breach. If Real Madrid are found guilty, they could be handed a defeat for administrative reasons.

COPE points out that the Pamplona side are unlikely to appeal.

However, there are long-standing implications. Each opponent that Real Madrid face could challenge them on Mastantuono’s presence should the teenager take the field, leaving Alonso’s side vulnerable to taking a loss.

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