The Chile international completed a £35m move to the Gunners from Arsenal last month, penning a long-term contract with the north London side.
The 25-year-old was joined by fellow new recruits France international Mathieu Debuchy, goalkeeper David Ospina and teenager Calum Chamberlain.
Arsene Wenger’s side are set to face Europa League runners-up Benfica before facing Ligue 1 outfit AS Monaco in The Emirates Cup this weekend.
Here is the best of the photos from Arsenal training.
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