Put it this way.
First game - Pereira was easily our best player.
Second game - Pereira and Sanchez our best players.
Third game - Pereira and Sanchez our best players.
Fourth game - Pereira and Sanchez our best players.
It's basically been the two of them in every match (Sanchez didn't play in the first one), and they've been so far ahead of everybody else it's kind of embarrassing. It's great for them, kind of worrying in regards to everybody else.
Considering Fred has only just had his first appearance as a late sub, Matic came back late and now picked up a knock, and Pogba not back yet, it should be pretty much a certainty that Pereira will start the first match and (as long as he performs well) likely the next few after that.