By FOX Sports Staff
The Czech tactician saw his side dismantle the Nerazzurri to end their hopes of qualifying for European competition for the first time in 17 years.
But they're not assured of a place in the Europa League as Lazio are currently two points behind fifth-placed Udinese who occupy the final Europa League berth.
With just two games left, it is set to be a three-way battle for fifth place with city rivals Roma close on their heels as they have the same number of points as Lazio.
"Now there are three teams fighting for the Europa League. If we win the last two, I am sure we can make it," Petkovic confidently predicted after the game.
"We are playing very well, although Inter deserved something more tonight [Wednesday].
"We had chances even after going 3-1 up, but we weren't clinical enough. I compliment my players for the result and for extending our positive streak."
Lazio face Sampdoria and Cagliari in their final two games and have a better head-to-head record when compared to Roma and Udinese, giving them a slight advantage should the three teams be level on points at the end of the season.