David Luiz appeared to hint at the level of disharmony at Arsenal under Unai Emery after Mikel Arteta earned his first win as manager.
After false starts against Bournemouth and Chelsea, the Gunners easily triumphed over Manchester United on New Year's Day to move up to 10th in the Premier League standings.
Emery was sacked last month after a disaster start to the season, with form not improving under interim coach Freddie Ljungberg, amid reports of squad unrest and players openly mocking the Spaniard.
Luiz, who was brought to the club by Emery, says the players "believe in what we are doing", seemingly confirming further reports that the former manager's tactics were not approved of by the squad.
He told BT Sport: "It was great. We have to be humble enough to admit, physically we were not ready. So we showed that today, when physically you aren't there you need heart.
"This team is in the moment to change a lot of things. We are going to do big things in the future, but step by step.
"Mikel Arteta is a great coach, he was a great player. I think he can improve every player.
"In life when you are happy results can be different. If you work with happiness and believing what you are doing it is totally different.
"Our season started very bad but things can change."
