Walter Mazzarri said Inter had only themselves to blame for wasting chances after their 2-1 defeat to Atalanta.
Giacomo Bonaventura got the goal in the final minute with a free header from a set play at the back post.
“Clearly we just needed to mark the goalscorer and we wouldn’t have lost,” Mazzarri told Sky Sport Italia.
“We can’t think to start the second half with four or five chances to put in the net and not score any of them.
“Atalanta could’ve scored earlier when Jonathan performed a goalline clearance. Atalanta are a good side and came here with no pressure, so it was obvious they could worry us.
“Inter had a great second half in which we threw everything at them, but we hit the woodwork repeatedly and I think we’ve done that more than anyone else this season.
“We practically gave away the first goal, then we gave away the second because of some poor marking. That’s football, if you don’t take your chances then you get punished.
“When the second half starts like that, we need to score at least two goals. It’s incredible to dominate like that and still be on 1-1. It gave Atalanta confidence too, as time went on and they were still in it.”
Bonaventura was unmarked and Mazzarri revealed there was a very specific person to blame for that goal.
“I can’t tell you who was meant to be marking him. We moved to four at the back in a bid to get the victory, but someone was meant to be marking Bonaventura and he forgot. I won’t say the name. If I do, then tomorrow he’ll get torn apart in the media, so we’ll save him that.
“I removed Cambiasso as I wanted more technical players who could win the game at all costs like Ricky Alvarez.”
Mauro Icardi scored and also showed off a T-Shirt with a message for his girlfriend Wanda Nara, the ex-wife of former Sampdoria teammate Maxi Lopez.
“He is a very strong finisher, though he still doesn’t always make the right decision. He is still feeling pain after months out and needs time to find his form.
“When I played we had different lives and no Internet or Twitter. If you want to be a Coach in modern times, you have to live with this sort of thing. There are players who listen to music by themselves before the game to prepare, which we never used to do.
“This is the youth of today and if I were to run around trying to stop all the things I didn’t like, I’d go mad! I even tried to tell the lads not to celebrate after scoring, as we have often lost focus and conceded straight away.”