Napoli coach Walter Mazzarri refused to use the word title after his side's impressive 2-0 win at Roma kept them well and truly on Serie A leaders AC Milan's heels.

The clash in the Italian capital was viewed beforehand as an important benchmark to see if Napoli have what it takes to win big games under pressure.

And they came through with flying colours as an Edinson Cavani brace -- the first from the penalty spot -- gave them a double over Roma and also ended their opponents' own interest in the title.

"Like I said the other day, we don't use that word," Mazzarri said when asked about the title.

"We're improving and I have to pay tribute to my players, they took a step up in quality from every point of view.

"(Ezequiel) Lavezzi played almost 90 minutes for Argentina in midweek and the tasks I gave him unleashed Cavani.

"If someone sees a team-mate in trouble, he goes to his help and that's a source a great satisfaction."

Lavezzi was at the centre of a controversy as TV pictures showed he and Roma's Aleandro Rosi spitting at each other.

But Mazzarri jumped to his player's defence.

"I spoke with Lavezzi and he was provoked. This also happened to me when I was a player (being spat at) and it's a terrible thing, humiliating.

"He was provoked and reacted, that's not right but it shouldn't be forgotten.

"I would like to think it will be taken into consideration the fact that he was provoked out of the blue (when a sanction is imposed).

"It was stupid to react but these things will be analysed in a different way."

Rosi, however, claimed it was the Argentine who had started things.

"Lavezzi was on edge for a while and before the spitting he had elbowed me in the stomach during a break in play," he said.

"I was the first to spit but he started it. He was the first one to provoke something."

Roma coach Claudio Ranieri admitted that the title race was over for his team, who now trail Milan by 13 points, but with a game in hand.

"Fighting for the scudetto at this point to me seems a big ask," he said.

"But it seems that it just takes one defeat for people to say the toy is broken.

"We have to change objectives now, roll up our sleeves and see where we can finish.

"It's true that this year we're not the same team as last season, we're not running like we did before and we have to try to understand why."

As for the spitting incident, Ranieri condemned both players: "Spitting is the most ignoble act there is."