Trent Alexander-Arnold subbed off on La Liga debut as Real Madrid fans spot major problem involving Kylian Mbappe

Real Madrid fans have spotted a major problem between Trent Alexander-Arnold and Kylian Mbappe following their victory over Osasuna.

Alexander-Arnold, who joined from Liverpool for £10 million, made his La Liga debut for Real against Osasuna, having appeared for his new team earlier this summer in the Club World Cup.

He started every game in the United States other than their semi-final defeat to Paris Saint-Germain.

And the England international got his first taste of Spain's top flight on Tuesday.

Xabi Alonso's side beat Osasuna 1-0 thanks to a second-half Mbappe penalty.

Mbappe is off the mark in the new campaign, having bagged an impressive 31 league goals last season.

He could set his sights on a better haul this time around following the additions of Alexander-Arnold and Alvaro Carreras, who should provide plenty of chances on the flanks.

Trent Alexander-Arnold in action for Real Madrid against Osasuna. Image: Getty

But Real fans are concerned about Alexander-Arnold, who was replaced in the 68th minute, crossing the ball into the box given Mbappe isn't prolific with his head.

One X user wrote: "Trent crossing the ball for Mbappe to head it #DoesHeKnow."

A second said: "Trent and Carreras crossing the ball to Mbappe to head the ball. Who's gonna tell them?"

A third added: "Who is Trent crossing the ball to?"

A fourth claimed: "Trent should realise crossing with those attackers is pointless."

Another suggested: "This is why we need Gonzalo [Garcia]."

Kylian Mbappe looked a threat when he appeared on the right wing. Image: Getty

Alonso appeared to sense the problem during the game and made an in-game tactical switch, moving Mbappe to the right wing, where he looked a threat.

Real open their league campaign with three points as they return to action on Sunday when they travel to Oviedo.

Alexander-Arnold is expected to keep his place in the starting XI after making his debut tonight.

Despite the issue against Osasuna, Alonso is unlikely to drop Mbappe, but he could introduce Gonzalo Garcia into his starting XI following his emergence at the Club World Cup.