AS Roma's Italian forward Fabio Borini (L) in action against Inter's Ivan Cordoba (R) on his way to score the 3-0 lead during the Italian Serie A soccer match between AS Roma and Inter Milan at the Olympic Stadium in Rome, Italy, on February 5, 2012.
Inter were routed 4-0 at Roma on Sunday as the top five sides of the Seire A all failed to win.
Juan opened the scoring in the 13th minute For Roma and Fabio Borini doubled the hosts' lead before half-time. Borini added a third shortly after the break and substitute Bojan Krkic capped a great afternoon for Luis Enrique's side by notching their fourth a minute from time.
It was a miserable return to the capital for Inter's former Roma coach Claudio Ranieri, extending the Nerazzurri's winless run to three games.
Ranieri admitted that Inter were in crisis after they won the Milan derby.
"For the last few weeks we have no longer been ourselves. We concede too many goals and can't seem to play the football that we know we can," he said.
"We probably had a comedown after the derby victory and lost something in psychological terms. From Tuesday we must react, because we cannot carry on like this.
"We all have to rediscover ourselves on a mental and physical level. We've fallen many times and got back up, so we will do it again," Ranieri said.
For Roma, it was a first win in three games, which lifted them to the sixth place in the standings - two points behind fifth-placed Inter.
Roma head coach Luis Enrique praised his side's performance and demanded consistence.
"It was a great day for us and a wonderful victory after the defeat to Cagliari," he said.
"But it won't count for anything if we don't find consistency every single week. How much of this result was down to Inter playing badly? We won 4-0 and were superior from the first to the 90th minute. We deserve the credit for that," he said.
League pacesetters Juventus were frustrated in front of their own fans by a Siena side who were good value for a 0-0 draw in Piedmont.
Juve did all of the attacking in a one-sided game, but they failed to create any major chances as the Tuscans defended resolutely.
AC Milan failed to take advantage of Juve's draw as they were also held to a goalless draw in their game against Napoli at the San Siro.
Robinho missed the best chances of the game for Milan, who ended the game with ten men after Zlatan Ibrahimovic was sent off midway through the second half.
Napoli failed to make the most of their one-man advantage for the final 25 minutes and were left still waiting for their first win in five games.
Fiorentina secured back-to-back league victories for the first time this season as they won 3-2 to prevent Udinese closing the gap at the top of the table.
Genoa risked throwing away a three-goal lead before seeing off Lazio 3-2 on a frozen pitch at the Stadio Luigi Ferraris.
Luciano's own goal gave Parma a 2-1 victory in the mid-table clash at Chievo.
Palermo continued their fine run of form with a 2-1 victory over ten-man Atalanta at La Favorita.
Novara still await their first win in 2012 after being held to a goalless draw by Cagliari.
Strugglers Lecce and Bologna drew 0-0 in their match at the Via del Mare stadium. Both teams have shown improved form recently, with Lecce beaten just once in five games and Bologna enjoying a five-game unbeaten record.