Kylian Mbappé was shown a straight red card for a reckless challenge in the first half of Real Madrid’s nervy 1-0 LaLiga win at Alavés on Sunday.

Madrid had just taken the lead in the 34th minute with an Eduardo Camavinga goal — after Raúl Asencio had an earlier goal disallowed for a foul — when Mbappé was dismissed in the 38th minute, after a VAR check, for his high tackle on midfielder Antonio Blanco.

The player count was leveled in the second half, after Vinícius Júnior was caught on the calf by defender Manu Sánchez, who also was sent off.

Madrid could not afford to drop points in their bid to keep pace with Barcelona in the LaLiga title race. They were also without suspended coach Carlo Ancelotti, who received his fifth yellow card of the season during Madrid’s 2-1 loss to Valencia on April 5. The win leaves them four points behind leaders Barça, who won 1-0 at Leganés on Saturday.

“Kylian isn’t a violent lad for sure; he’s said sorry, he’s aware of the mistake he made,” said assistant coach Davide Ancelotti, Carlo’s son. “It’s a clear red-card challenge, and he’s suffered the consequences.

“All the little fouls they committed on him made him react in that way. It wasn’t the right way, I’m not justifying it, but that’s what happened.”

Mbappé’s red card was his first since joining Madrid last summer.

Previously, he was sent off three times for Paris Saint-Germain — once in Ligue 1 and twice in cup competitions.

Madrid must now await news on the length of Mbappé’s ban from the Spanish football federation, with the forward likely to miss upcoming league games against Athletic Club and Getafe.

The defending LaLiga champions then face Barcelona in the Copa del Rey final on April 26.

Mbappé’s red added to Madrid’s tough week, in which they lost 3-0 at Arsenal in their Champions League quarterfinal first leg on Tuesday.

“What happened [against Alavés] made it a bit more difficult for us, but winning gives us confidence for what we want to happen on Wednesday [in the second leg],” Davide Ancelotti said.

Midfielder Dani Ceballos, who made his return from injury on Sunday, said: “We need the players to give 200%,” when asked about the possibility of a comeback against Arsenal. “The only chance we have is for everyone to be together. We expect an incredible atmosphere at the Bernabéu.”

The game at Mendizorroza was briefly paused in the second half by referee Cesar Soto Grado after chants of “Asencio, die” from the crowd, aimed at Madrid defender Asencio.

“It’s disappointing,” Ancelotti said. “But it’s not up to us to take action. We don’t want it to happen, but it is what it is. It’s up to the referee to act.”