I am a player who was known for their tenacious style and fiery spirit, and I had a memorable spell with Arsenal. Who am I?

1. I played primarily as a central midfielder and sometimes as a right back.
2. I joined Arsenal from a Spanish club and had a difficult start to my time in London.
3. I was nicknamed 'The Pitbull' for my aggressive playing style.
4. I helped Arsenal win multiple FA Cups during my time at the club.