Osimhen and Kvaratskhelia both score again as Serie A leaders Napoli moved 18 points clear at the top of the table thanks to a routine away victory over Sassuolo.
Khvicha Kvaratskhelia opened the scoring after only 12 minutes when he shot low into the corner after a fine run.
Victor Osimhen hit the woodwork before he made it 2-0 after 33 minutes when he powerfully shot on the turn and beat Sassuolo goalkeeper Andrea Consigli at his near post.
Osimhen has now scored in seven successive Serie A matches for Napoli, who are trying to become Italian champions for only the third time and for the first time since 1989-90.
Napoli added a third goal in injury time through Giovanni Simeone, but it was ruled out after a video assistant referee check showed there was an offside.
Napoli have only lost one league game all season and have 62 points from 23 matches, with second-placed Inter Milan on 44 points.
Inter have a game in hand, which they play on Saturday when they entertain Udinese at San Siro.
Napoli finished above Liverpool in their Champions League group and play away at Eintracht Frankfurt in the first leg of their last-16 tie on Tuesday.