Guardiola informed his players that he would be quitting the club at the end of the season before then announcing his imminent departure to the media.

Onlookers were surprised that Barca's star forward was not at the media conference but Messi explained that the occasion would have been too much for him.

"I wholeheartedly want to thank Pep for everything he has given me in my professional career and personal life," the Argentina international wrote on his Facebook page.

"But due to the emotion I feel, I preferred not to be present at Pep's press conference, especially because I knew that they (the press) would have been focusing on the faces of the grieving players and this is something that I did not want to show."

Guardiola, who will be replaced at the helm by assistant coach Tito Vilanova, has led Barca to 13 titles since taking charge of the club in 2008.

Vilanova, 42, joined Guardiola when he replaced Frank Rijkaard in 2008, but he has been very much in his shadow, until now.

The most notorious incident involving Vilanova as Guardiola’s assistant dates back to last August in stoppage time of the Supercopa return leg between Barcelona and Real Madrid at Camp Nou.

A reckless challenge by Marcelo on Cesc Fabregas sparked a scuffle between players of both clubs, and ended with Jose Mourinho poking a finger in Vilanova's eye.

Last October, Vilanova faced a more important battle as he underwent emergency surgery to remove a tumor on his parotid gland.

Thankfully, the operation was a success, and after a few weeks he was able to resume his job without trouble.

According to Barcelona sporting director Andoni Zubizarreta, Vilanova's appointment as successor to Guardiola is "a logical decision" because he "represents the same style of play and the same philosophy".