Antonio Conte called on Arturo Vidal to improve after conceding a penalty that gave Inter brief concern in their 6-2 win over Crotone.
The Nerazzurri were ultimately comfortable victors at San Siro on Sunday as Lautaro Martinez scored their first perfect hat-trick since Mauro Icardi's against Atalanta in March 2017.
However, Inter had been level at 2-2 at half-time following Vidal's needless error.
After Martinez's first effort and a Luca Marrone own goal turned the match around following Niccolo Zanellato's Crotone opener, Vidal charged towards Arkadiusz Reca and stepped on his foot in the area to concede a penalty, which Vladimir Golemic converted.
Inter coach Conte was worried at that stage the setback might affect his side, looking to win an eighth successive league match for the first time since 2008.
But Vidal was replaced at the interval and an assured second-half display saw Martinez score twice more either side of an excellent Romelu Lukaku effort, before Achraf Hakimi completed the scoring.
Conte told Sky Sport Italia: "We did well to turn it around, then the naivety on the penalty could have created anxiety and nervousness.
"But we did well to get back on track and bring home another win.
"We had good answers today, also because we had started in the right way. Then there was this corner where they surprised us [for Zanellato's goal]."
The penalty was the only foul Vidal committed before his premature withdrawal, but he won just two of his five duels and Conte was not impressed.
"Arturo has important margins for improvement," Conte said. "He definitely needs to work. Keep your head down and keep working.
"Nobody is guaranteed a place here and he has to prove he deserves to play. He must do much better than what he is doing.
"From what we've seen so far, there are too many ups and downs, and we can't afford them. He knows this, he knows he has to train harder.
"Maybe when you play in big teams, sometimes this aspect takes a back seat. Here instead you have to raise the level, he knows that. We'll give him time."
Far more impressive was Lukaku, who created the first Inter goal for Martinez, had a hand in the next two and then scored the fourth before he hobbled off with an injury.
Having seen his outstanding number nine net his 35th goal in his 50th Serie A game, Conte will hope he does not have to face a spell without the striker.
Inter are in action again as soon as Wednesday, facing Sampdoria, and the coach was waiting to hear more on Lukaku's problem.
"He told me he had a small quadriceps strain," Conte said. "We'll see tomorrow if he's at risk for the Sampdoria game.
"We took him off straight away. I don't think it's anything serious."