Leonardo believes Sunday's clash with on-form Udinese represents “the toughest test” of his Inter yet.
The Coach has won all five games under his tenure between Serie A and the Coppa Italia, but the Friulani held leaders Milan to a 4-4 draw at San Siro and won 4-2 in Genoa.
“We will be facing players in great shape, who are getting excellent results and we must be very careful,” noted Leo.
“Alexis Sanchez and Antonio Di Natale form a very interesting partnership that is extremely difficult to defend against.
“I think tomorrow might be truly the toughest test we've had yet. In any case, we too are in a positive period of form and I trust my team to read the situation with their tactical intelligence.”
The 12.30 local time kick-off, 11.30am in the UK, represents a new dawn for Leonardo.
“This is the first time that I, as a Coach, have had a game at this time. It changes our preparation a bit, but I'd say more or less everyone in Serie A has grown to accept it now.”
Leonardo has been a huge success since replacing Rafa Benitez over Christmas, but there is increasing talk of Jose Mourinho returning next season, moving him to a directorial role.
“I live each day as it comes. I experience this great moment with the team and focus only on that.
“As for the Scudetto race, I don't think anything is decisive right now. There's a long way to go. The important thing was to close the gap from the top and we have done that.”
Benitez famously demanded at least four new signings, but Leo seems content with just Andrea Ranocchia to replace the injured Walter Samuel.
“We don't need anyone, as the squad is already competitive. If there is an additional resource to make the team stronger, then that's welcome, but it has to be introduced the right way.”
Coutinho is back in the side after a long injury lay-off alongside Thiago Motta, but Diego Milito, Wesley Sneijder, Samuel and Julio Cesar are out of action.
Inter squad: Castellazzi, Orlandoni, Gallinetta; Cordoba, Zanetti, Lucio, Maicon, Ranocchia, Materazzi, Chivu, Santon; Stankovic, Thiago Motta, Mariga, Cambiasso, Obi, Coutinho, Nwankwo; Eto'o, Pandev, Biabiany
Think you know your Italian football? Share your knowledge, tips and comments to win cash prizes in OLBG's tipster competition  - £5,000 monthly.