It depends what team is playing but I still find it surprising how big of an impact a red card in football can have and within minutes turn the whole game completely upside down. After the red card it was only Roma, but then the penalty put the nail in the coffin for Sassuolo regarding their mental resilience. I think they really felt broken at that point because everything in that game turned against them. The second goal was to be expected somehow as Roma was pressing hard for it.
Of course, the impact will be huge for the club that gets a red card. In this case, after Sassuolo received a red card, Roa was ultimately able to score 2 goals, even though the only one was a penalty. But this really has an impact on a team. 10 against 11 people will definitely have an effect. Even though Sassuolo had already taken the lead, Roma was lucky enough to receive the red card their opposing team received.
For next week, Napoli will face another big team. This is like a disaster that keeps happening to Napoli in a row. After losing to Ral Madrid, then Inter, and then having to play Juventus next week. This will definitely have an impact on their mentality. And this will be a very big challenge for Mazarri.
For Inter Milan the situation is becoming more and more comfortable as they most likely will win their next home game while Juventus Turin is battling Napoli. I think Juventus Turin won't lose the game, but if they do and Inter Milan wins the game we are about to see what we saw last season with Napoli running away in the table from everyone else.
AC Milan has a game against Atalanta, which I don't consider easy either, but AC Milan is a big favorite there.