The giant Austrian international returns to the San Siro on Wednesday for the second Champions League Group A encounter and is keen to show the European champions what a great player they could have had if he had felt more like a part of the family.
"Now I set three alarm clocks. I am more disciplined these days." Arnautovic told reporters.
"What matters here at Werder is the team. At Inter it was different. There everyone does their own thing."
The 21-year-old was chased by Inter's sporting director Marco Branca for months but when he finally joined on loan from Twente Enschede last year, former coach Jose Mourinho took an immediate dislike to his sometimes lax approach.
He barely featured during Inter's stunning treble success last term and the Serie A champions never considered taking up their option so Twente sold him to Werder.
The holders sold Mario Balotelli to Manchester City in the close season as well as letting Arnautovic go, meaning usual starters Milito, Samuel Eto'o and Goran Pandev are their only established forwards with youngster Coutinho still very green.
"There's no lack of quality alternatives in attack. Players like Milito, Eto'o, Pandev and Coutinho aren't easy to find," Benitez said after Saturday's 1-0 defeat at AS Roma, his first league defeat of the fledgling campaign.
Inter Milan: 1-Julio Cesar; 13-Maicon, 6-Lucio, 2-Ivan Cordoba, 26-Cristian Chivu; 17-MacDonald Mariga, 19-Esteban Cambiasso, 5-Dejan Stankovic; 10-Wesley Sneijder; 9-Samuel Eto'o, 27-Goran Pandev
