I love you, take my watch! – How Arnautovic earned a special gift from Mourinho
The Austria international endured a difficult loan spell at San Siro in the Portuguese's final year in charge, making only three Serie A appearances in the Nerazzurri's treble-winning season.
Mourinho later described Arnautovic as "a fantastic person with the attitude of a child" and the club declined to take up the option to sign him permanently from Twente, allowing him to join Werder Bremen.
Arnautovic, though, retains a fond memory of Mourinho that stems from a desperate attempt to avoid a telling-off after his lack of punctuality caused problems on a pre-season tour.
"We were at Abu Dhabi for pre-season with Inter in 2009," he told The Daily Mail. "I overslept for breakfast. Late number one.
"Then there was the team meeting. The hotel was huge and my room was on the 75th floor. I am waiting for the lift and I press and I press and still I have got seven minutes so I am okay. But then I still didn't make it. Disaster. Number two.
"Then, before we meet for the game, it was happening again and I was like: 'He is going to kill me'. So then we fought a little bit and I was out of the team that day, training on my own.
"Back in Milan, I thought we were training in the morning and I went in just perfect. There were no cars there. We were actually training in the afternoon that day!
"Mourinho is there with his staff and he stands up and starts applauding and laughing. He said: 'You are my man. You come here five hours before training. I love you! Here, take my watch'. I still have that watch in my house."
Thanks #COYI #COYI #COYI @westham SUPPORT
A post shared by Marko Arnautovic (@arnautovic_10) on Sep 16, 2017 at 11:29am PDT
Arnautovic endured something of a troublesome relationship with staff and team-mates at Bremen before leaving for Stoke City in 2013, where he had a far happier spell.
The 28-year-old, who cost West Ham a reported £28m in the transfer window, admits his attitude as a youngster did not help matters early in his career but says he made an important decision to turn away from his friends' life of crime and focus on football.
"Everywhere they threw me out," he said of his days in youth teams. "I didn't give a f*** about what I did. I didn't care about anyone or listen to nobody, only my father or mother.
"I would fight my coaches and say: 'Who are you to scream or shout at me? Are you my dad? Talk to me normally'. Everywhere I went, Rapid Wien or Austria Wien, there was always a problem. I just wanted a coach who said: 'Just go out and win us the game'.
"My parents tried but I chose the other way, to be on the street. I wasn't a gangster or anything but two friends went to jail. Nobody was killed but it was fights on the street and things.
"When you are on the street, if someone walks towards you it's better to look down. But we were always looking at people in the eye to try to provoke something. So we would fight.
"Then some of them started robbing. I am happy I got away as that wasn't a good time. I was telling my friends: 'Don't go in that house to rob or that shop as you will end up in jail'. I told them to go and work and have a good life. Robbing someone is not a good life.
"But look, let's not exaggerate, most of the time we were just in the park playing football. Football was everything.
"If I had continued to be that person I was then, I wouldn't be here now. I was scared a career in football would never happen if I carried on. I knew I had to go away and see some different things and calm down."