It was announced on Thursday that the Chilean international had signed a long-term contract after joining from Barcelona on Thursday.
Arteta is certain the 25-year-old will prove to be a big asset and says he has all the qualities to succeed in the Premier League.
“I'm delighted,” he told Arsenal Player. “He’s the type of player we were looking for.
“At some stage [last season] we didn't have that pace up front with the injuries we had, but this year we will. We will be a threat in behind teams and he'll give us another option.
“He's a character, too. He's a fighter and very ambitious. I think he's the type of player that the Arsenal fans will really like.
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“It is a very good statement to show where we are going. I think we are going in the right direction, the club is ambitious, the directors are ambitious and we are going to fight for big aims.
“The FA Cup was good but not enough and we want to improve on that.”Copyright 2016 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source