The pair are as mad as hatters with Balotelli world renowned for his wacky antics, including setting fire to his bathroom with fireworks and walking into a school full of children and asking for the toilet.
Former wildman Cassano has calmed down slightly now he is married with a child but he loves nothing better than dancing around the pitch in only his underpants after a big game.
Thursday's match is no laughing matter, though, and coach Cesare Prandelli is considering splitting the duo up after forward Antonio Di Natale replaced Balotelli off the bench to score in the 1-1 draw with Spain in their group opener.
Croatia, who beat Ireland 3-1 in their first match, pose a very different threat to Spain given their aerial prowess and Prandelli must decide if Balotelli's strength and height outweigh the fact he struggled against the holders.
"He is a guy of 22 years of age, he is on the road to finding maturity. What I ask is for him to play simply. To help the team and to stretch the play behind the opposition defence," Prandelli told reporters while reflecting on Balotelli's bad miss against Spain when he was caught in two minds and tackled.
"When he makes a mistake he must think that there will be other opportunities...and find the conviction to make the right decision next time.
"The thing to underline is that he won the ball himself (in that chance). When you have two choices it slows you down."
The moody Balotelli, who at time produces outrageous skill, is not the only player who risks being dropped in Poznan.
Cassano returned in May from five months out following heart surgery and although he played well against the world champions, he failed to manage the 90 minutes.
"I want to understand who is most tired," said Prandelli, whose forwards are all on the small side except for Balotelli.
Prandelli even said he was re-evaluating his new three-man defence for the Croatia test but wholesale changes after a well-received display against Spain would worry Italian pundits.
Croatia were also praised for their fast-paced but disciplined dismantling of the Irish with striker Mario Mandzukic impressive in the air and Nikica Jelavic always dangerous as Luka Modric pulled the strings in midfield.
Coach Slaven Bilic thought his side came close to perfection against Ireland but he has been in charge too long and is too much of a tough task master not to motivate his charges.
"We will be more relaxed and not under such pressure after the opening victory, but it can't be much better than this in the next game," he said.
"Italy are strong, they think about us and about our play. Prandelli respects us. They have a team and players who can dominate on the pitch. For me, they are not weaker than Spain, especially with Prandelli in charge."