Mikel Arteta reportedly gave his Arsenal squad a warning that he'd be watching them from the stands before Saturday's 0-0 draw with Everton.
Arteta was joined by Arsenal technical director Edu in the Goodison Park stands as the Gunners ground out a bore draw with the Toffees.
Freddie Ljungberg's final match in charge saw a number of big changes to the starting XI, with young players including Emile Smith-Rowe being introduced to the first team.
Arteta likely had a hand in selecting the much-changed team, which saw the likes of Alexandre Lacazette and Matteo Guendouzi named on the Gunners bench.
According to ESPN, Arteta spoke to his new Arsenal squad prior to Saturday's match.
He is reported to have told the players: "I will be in the stands tomorrow [Saturday] at Everton . I want you to know that I will be watching your attitude, your efforts, your body language.
"I will see what you do when we lose the ball, what your attitude is. Also, what you do when we have the ball."
Arteta spoke to the press for the first time as Arsenal manager on Friday, shortly after the club confirmed his appointment.
He explained that his mentor Pep Guardiola taught him to be ruthless, and his message to the players suggests he intends to follow the Man City manager's lead.
"What I've learned mostly is that you have to be ruthless and you have to be consistent and you have to fit every day the culture of the club to create a winning mentality," said Arteta.
"To sustain it is even harder, so every day is important, every act is important, every organisation is important. His work-rate is incredible, how inspirational he is to people is incredible.
"But for me, the secret is that the people, the players and the staff, have to believe what they're trying to deliver. You have to be able to transmit it, and people will buy into that.
"When you do that, then you are a team and everybody's together and united you're stronger."