Kylian Mbappe signed a five-year deal at Real Madrid in July after the expiry of his Paris St-Germain contract
Kylian Mbappe scored his fourth goal in three La Liga games as Real Madrid came from behind to earn an emphatic victory over Espanyol.
Despite their dominance, the unbeaten hosts trailed nine minutes into the second half when Thibaut Courtois diverted Jofre Carreras' cross into his own net.
But Espanyol's surprise lead lasted only four minutes as Jude Bellingham's pass squeezed beneath goalkeeper Joan Garcia, allowing Dani Carvajal to fire into an open goal.
The turnaround was complete with 15 minutes remaining when Rodrygo met Vinicius Junior's cross, before substitute Vinicius added a third three minutes later and Kylian Mbappe converted a late penalty.
The hosts fired 14 shots at goal in a frustrating first half, with Mbappe going closest when he was denied by Garcia at close range.
Carlo Ancelotti's side ended the match with 31 attempts in total, compared to Espanyol's one - which arrived in the 68th minute - and Real never panicked after falling behind in the second half.
Mbappe, now with six goals in his first eight appearances for the club since moving from Paris St-Germain in the summer, assisted Vinicius with a perfectly weighted through-ball before slotting in his spot-kick, awarded after Endrick was fouled by Carlos Romero.
Victory took Real up to second in La Liga after four wins in their opening six games - one point behind leaders Barcelona, who travel to Villarreal on Sunday with a perfect record.
Ancelotti's side have also equalled the second-longest unbeaten run in La Liga, behind only Barcelona, who went 43 league games unbeaten between 2017 and 2018.
