Ivan Perisic added the other but the match will belong to Icardi’s brilliant display – who passed two century marks in style.
Ending the day with 103 goals in his Italian league career, the 25-year-old became the sixth-youngest player in Serie A history to score 100 or more.
The players ahead of Icardi on the list are: Giuseppe Meazza, Silvio Piola, Giampiero Boniperti, Felice Borel and Jose Altafini – all legendary footballers.
Icardi also reached an even 100 goals for his Inter Milan career across 172 appearances in all competitions.
What’s more is that the performance came against Icardi’s former team, which always seems to bring the best out in him, such as his brace in Inter’s 3-2 win in October.
Perisic put Inter ahead with a looping header 26 minutes in for his first goal since early December before Icardi took over.
Four minutes later, Icardi converted a penalty following a foul on Rafinha to reach the century mark.
The Argentina striker then fooled goalkeeper Emiliano Viviano and defender Gian Marco Ferrari with a splendid backheel goal.
Icardi completed a hat-trick by knocking in a rebound off a shot from Rafinha then scored with a high bouncing shot shortly after the break.
Inter moved into fourth place, two points ahead of Lazio – who were due to host Bologna later on Sunday.