The Giallorossi lost 3-0 at Siena on Sunday while a penalty from Zlatan Ibrahimovic allowed 10-man Inter to beat Empoli 1-0.

"I don't believe it's over," Spalletti said. "It's early days yet.

"It's going to be difficult but we have to continue to believe in ourselves. We have seen that against inferior teams you risk giving a bad performance."

The surprise outcome in Siena brought to an end Roma's four-game winning run in the league.

"We made too many mistakes against Siena and we paid for them," said Spalletti.

"It's clear that Inter have shown character, maturity and determination throughout this campaign, something which we lacked against Siena.

"However, Inter have had episodes going in their favour and that has helped them."

Spalletti was referring to the controversial penalty given to the Nerazzurri which led to Ibrahimovic's winner on Sunday.

Empoli's Ighli Vannucchi was adjudged to have cleared the ball with his hand inside his area while video replays showed he had in fact used his head.

Empoli, who had a numerical advantage for the entire second half following the sending off of Patrick Vieira, did have a chance to equalise but goalkeeper Julio Cesar saved Luca Saudati's penalty.

Inter coach Roberto Mancini admitted his team had luck on their side as they maintained their unbeaten run this season.

"The two penalties should not have been given," said Mancini.

"But I am happy for the win because it was a really hard triumph.

"For the third game in a row we had to play with 10 men and we really complicated our lives."

Third-place Juve also endured a challenging encounter at home to bottom side Cagliari.

The Bianconeri missed out on an opportunity to cut the deficit to two points with Roma as they were held to a 1-1 draw.

Pavel Nedved equalised a minute after Paolo Bianco had given the visitors the lead.

"We knew it was going to be a difficult game," said Ranieri. "Cagliari created problems for us, we wanted to win at all costs and trim our deficit with Roma.

"We tried to win but we were fragile, allowing Cagliari to hit us on the counter-attack."

Juve, who are 12 points behind Inter and four behind Roma, travel to Udine next weekend.

Roma host Reggina next Saturday while Inter make the journey to Sicily to meet Catania.