Lionel Messi was back in full training with Barcelona on Wednesday for the first time since conceding defeat in his battle to leave the club.

Unlike Monday, when the 33-year-old Argentine superstar had to train alone under La Liga's coronavirus protocol, he joined up with the rest of the squad in the session taken by new coach Ronald Koeman.

A club statement reported that others returning to the main group were Philippe Coutinho, Sergio Busquets, Frenkie de Jong and Ansu Fati.

Messi faces another season with the Catalan club after losing his stand-off with Barca president Josep Maria Bartomeu over a 700 million-euro release clause.

The Argentinian superstar hit out at Bartomeu in his bitter announcement last week that he was staying and warned he was expecting to see progress, saying: "There is a new coach and new ideas. That's good, but then we have to see how the team responds and whether or not it will allow us to compete at the top level."

Adding to Messi's discomfort his two closest friends at Barcelona, Luis Suarez and Arturo Vidal, are expected to join Juventus and Inter Milan respectively.

Koeman's first match in charge since replacing Quique Setien in the aftermath of last month's humiliating 8-2 Champions League pounding by Bayern Munich is a friendly against third division opposition on Saturday.