Their performance was hampered by a serious injury to Fabio Quagliarella and Felipe Melo’s sending off within the opening 16 minutes.
Del Neri said: “Playing with 10 men is complicated enough, then losing Quagliarella certainly didn’t help.
“It wasn’t easy to manage the game with Amauri and Ale Del Piero coming back from injuries of their own.
“We could have created a few chances with better balance, but I can say little because Melo’s sending off changed the game.
“It’s the second time that we’ve played with 10 men for almost the entire game. We’ll roll up our sleeves and find a solution for Sunday’s game against Napoli with the idea of recovering as much energy as possible as soon as possible.
“If we want to fight for an important objective, we have to judge the situations well.”