It was a disjointed performance from the Nerazzurri, who were undone by a first half penalty from Dominic Berrardi. It was a nightmare start for a team who were looking to compete for the Serie A title this season, especially after such a promising summer transfer window.
Spalletti believes that his side performed reasonably, but he also confessed that things need to change when they face Torino next week.
"I think we did well today and we played the game we had too. Even so, we lost possession of the ball too many times. We will have to be better starting next week" Spalletti told DAZN, as per Calciomercato.
Inter dominated possession throughout the match, but they were left undone by Sassuolo who executed their counter-attacking tactics to perfection. However, Spalletti wasn't too complimentary of his opponent's plan.
"Sassuolo? Well they did well but it's clearly easier to sit back and then counter. They pressed us well in the midfield but as I said, they pretty much just countered.
"They played very tight so it was hard for us to string passes. The football field wasn't the best too so it wasn't easy. Sassuolo didn't create that many chances but they scored on that penalty-kick."
Spalletti also discussed the performance of Inter left-back Henrique Dalbert who was hauled off at half time after a less than impressive first half performance.
"Dalbert? Well I think that he can do much better but he was okay at times. His crosses can be dangerous."