David Suazo had Inter in front and even with Pele's dismissal before halftime it looked as though three points were secure - before Borriello swooped for a spectacular equaliser five minutes before time.
"The red card affected the whole game. On the first booking the player made a mistake, but on the second you just need to see the replays to know the referee was wrong," said Inter coach Roberto Mancini.
"We must start by saying that referee Gianluca Rocchi is unfortunate when it comes to Inter, as it is not the first time he has penalised us. He did the same against Sampdoria."
Genoa felt they deserved more than a point from the Marassi meeting and Coach Gasperini explained why he left Capocannoniere Borriello on the bench in the first half.
"We had the opportunity to win this match and we had done well in the first period, too. Borriello had never rested up until now and he definitely needed it."