The men from Turin headed into their final Serie A match of the season knowing victory would see them into the UEFA Europa League.
However, Alessio Cerci's late penalty was saved in their 2-2 draw with Fiorentina, handing the European berth to Parma.
"Not even the cruellest scriptwriter could've come up with this ending. It is part of the Granata DNA, we have to suffer," Ventura told Sky Sport Italia.
"It has been a very important year, a great season and it's true we lost the chance to go into Europe over the last two rounds, but we never expected to be in there in the first place.
"A victory would've upgraded it to an extraordinary campaign. It would've been a return to Europe after 20 years, but also sending out a positive message for the future of this club and Italian football.
"We always played attacking football, focused on young talent and not that long ago we were in Serie B.
"I repeat what I said to the players, which is that defeats are part of the sport.
"There are seasons that make you proud of what you’ve done. I am proud of the players, I hope they are proud of themselves and the fans are too."
‘He instantly popped into our ratings as one of the best U21 midfielders in Europe. The impressive thing is Slot has made him into more of a no.6' Inside Ryan Gravenberch's transformation at Liverpool
‘I don’t think Liverpool would look at Ollie Watkins, a striker isn’t a pressing issue for them – it’s Arsenal who need one’ Former Reds star explains why his old club don’t need an out-and-out forward this summer
