Pioli told Italian media: "I expected more – we have put in a lot of hours and we have failed to win against Lecce and now lost against Roma.

"We have made incredible mistakes. In the first half the game was well balanced, but you can't concede a goal like we did to Zaniolo."

Pioli had taken over at the San Siro vowing his side still had a chance of claiming a Champions League place, but he admitted time is running out after this latest defeat.

He added: "We need to reverse this trend because the numbers are against us now.

"We made too many obvious errors. Roma did not put any pressure on us, but they only needed one mistake.

"We have taken a step backwards from a week ago. I don't think it's a lack of will or determination, but we have made technical errors and you pay for those mistakes."

Roma boss Paulo Fonseca praised his side's commitment after emerging unscathed from their third game in eight days.

Fonseca's men had followed their draw against Sampdoria last weekend with another draw with Borussia Monchengladbach in the Europa League on Thursday night.

Fonseca told his club's official website: "We fought very hard today – it's not easy to play three matches in a week right now, but the players deserved this result."

Fonseca denied that Zaniolo's match-winning display had anything to do with the player's very public war of words with Fabio Capello, who had criticised his performances.

Fonseca added: "I don't think it influenced him, but it's true that Zaniolo had a very good game. He scored a great goal and we've secured three very important points."

Roma's win moved them up to fifth place and, following a midweek trip to Udinese, they are due to face fourth-placed Napoli next week.

But Fonseca shrugged off talk of Champions League qualification, insisting: "Right now we just need to focus on our next game, then we'll see. The only thing that matters is the next match."