Dani Ceballos was named on the substitutes' bench for his first match in the Premier League.
The Spanish midfielder was the subject of much speculation in the summer transfer window, with north London rivals Tottenham also credited with an interest in the 22-year-old.
Ceballos starred for Spain U21s at the European Championships in the summer, and as a result was a player Real Madrid were keen to keep hold of.
It was suggested prior to that tournament that Ceballos could leave the Bernabeu permanently, with Zinedine Zidane unable to give the midfielder the game time he was desperate for.
However, after such a fine international tournament, Madrid were reluctant to lose him, only allowing a season-long loan deal.
And it was Arsenal who won the race for his signature, although former Chelsea and Manchester United manager Jose Mourinho does not think it was such a great idea.
Ceballos is undoubtedly a fine player, but Mourinho does not know where he fits in at the Emirates.
Speaking during his first appearance as a new pundit for Sky Sports, Mourinho said: "I think they have other Ceballos in the squad.
"I think he's a good player, but I think they have other Ceballos - when I see [Henrikh] Mkhitaryan, [Mesut] Ozil, Ceballos, they can play in different positions on the pitch but with very similar characteristics."
