At one stage, Ronaldo looked to be in danger of missing the game entirely after he was shown a red card in Juve's Champions League opener against Valencia for pulling Jeison Murillo's hair, but in the end he was only given a one-match ban.
Ronaldo made history with Saturday's score, becoming the first player to ever score 400 goals in Europe's top five leagues.
Lionel Messi is next best on 389.
Tahith Chong trained with Manchester United's first team ahead of their Champions League clash with Juventus as a replacement for Alexis Sanchez.
When asked whether there's no love lost between him and Juventus, Higuain said that he has a feeling of affection for the club because they treated him very well.
Ronaldo tapped home after 18 minutes before the hosts allowed Daniel Bessa to draw Genoa level after the break.
Allegri introduced Paulo Dybala off the bench and both he and Miralem Pjanic fired narrowly wide from distance, but Genoa withstood the late pressure to move 10th in the table and give Napoli the chance to close the gap to the leaders.
Napoli, coached by Carlo Ancelotti who will take his side to former club Paris Saint-Germain in the Champions League in midweek, were in front after 12 minutes on Saturday through a superb effort from Spanish player Fabian Ruiz.
His team sit second in Group H, behind Juventus, after a disappointed 0-0 draw with Valencia in their last game.
It was 2-0 11 minutes into the second half when Kevin Bonifazi headed home from a corner, and although Vanja Milinkovic-Savic's freaky dismissal with 15 minutes left gave Roma hope, they could not take advantage.