Antonio Conte said Scudetto challengers Inter gifted two goals to Lazio and were "scared" in the second half of their 2-1 Serie A loss on Sunday.
Inter's half-time lead was erased as Ciro Immobile and Sergej Milinkovic-Savic completed a comeback for Lazio, who leapfrogged the Nerazzurri into second position.
Conte's side started the weekend ahead of defending champions Juventus on goal difference but by the end of their trip to Rome, Inter were three points off the pace in the race for the Scudetto.
After the blockbuster showdown in the Italian capital, Inter head coach Conte told Sky Sport Italia: "I think it was a good performance, it's the result I didn't like and the way we conceded the two goals, as we gifted them to Lazio.
"We were not impeccable, but inevitably in these big games, the details become decisive and the margin of error becomes reduced. It's part of a growth process, there was some naivete and these lads must try to be more relaxed in these situations.
"We were too soft on the two goals. We had other situations this season where we had taken the lead and threw points away, for example also Barcelona and Borussia Dortmund [in the Champions League], games we had in our grasp and ended up losing.
"As I said, this is a growth process and we have to go through it so that we can face every situation the right way. Straight after the restart, it was as if we were scared. That has to improve.
"The lads worked hard and I thank them for that. We are trying to irritate the teams at the top, it was a 'head-to-head' with Lazio and we ought to be proud to have been in this situation in the first place. At the same time, we must improve if we are to continue causing problems up there."
Ashley Young had given Inter the lead on the stroke of half-time – the former Manchester United captain and full-back becoming the first English scorer for the Nerazzurri in Serie A since Paul Ince in 1997.
Young has impressed since arriving from Old Trafford in January and the veteran said: "We've got a lot of games coming up, we've got to dust ourselves off pretty quick and get ready for the next game.
"Of course we're still in it [title race], there are plenty of games, plenty of points up for grabs and I'm sure we'll get back to winning ways."