Andre Santos says he learned most about defending while at Arsenal.
Santos, currently on loan at Brazilian side Gremio, was heavily criticised for his substandard defending during his time at Emirates Stadium.
He said: "It was [in England] that I learnt I was a full-back, whose first priority is to defend properly and to get forward only when it's necessary."
Santos (above) also believes he lost his place in the Brazil team because to a lack of focus.
He added: "I made mistakes, which were more to do with me getting distracted than anything else. You have to maintain maximum focus because there are thousands of players who want your place."