Andriy Shevchenko scored both goals for European champions AC Milan in their 2-0 win at Chievo taking his season's tally to 10 goals.
Roma's Francesco Totti, Vincenzo Montella and Christian Panucci gave Fabio Capello's team a 3-0 lead at the break and Antonio Cassano added the fourth shortly after the restart.
Juve, who won 2-0 at Modena on Saturday, lead the table with 26 points from Roma and Milan on 24 points.
Inter Milan are in fourth place after their 6-0 victory over Reggina on Saturday.
Roma were at their devastating best against a Bologna side now facing the prospect of a fight against relegation.
Totti opened the scoring with a superb volley in the 15th minute before Montella made it 2-0, tapping home after Bologna keeper Gianluca Pagliuca parried a shot from Cassano.
The unfortunate Pagliuca again did well to keep out a header from Panucci but the Italy defender reacted quickly to hammer the ball home and give Roma a comfortable 3-0 halftime lead.
Cassano, who recently made his debut for Italy, wrapped up the win with a fine solo effort four minutes after the restart.
Capello was delighted with the performance, saying: "We gave little away and we created a lot of chances. To go far you need the kind of determination we showed today".
ANGRY CLASHES
Lazio's win will be remembered not for excellent finishing but for the angry clashes that soured the final half hour.
Roberto Mancini's side went ahead through Dejan Stankovic just before the break but winless Perugia fought back with an excellent strike from Fabio Grosso in the 62nd minute.
That should have set up a rousing finale but instead the match descended into chaos.
First, Perugia's Souleymane Diamoutene was sent off by referee Cosimo Bolognino for a late challenge on Giuseppe Favalli in the 71st
Both teams were then involved in clashes in the 84th minute with Perugia's Giovanni Ignoffo and Lazio's Sergio Conceicao dismissed after the fracas.
Three minutes later Bernardo Corradi put Lazio ahead with a beautifully struck shot from the edge of the area.
There was more off-the-ball incident as players and team officials squared up to each other on the edge of the pitch and Perugia coach Serse Cosmi was sent off.
In stoppage time Perugia's Marco di Loreto became the fourth player to see red after a wild challenge.
Simone Inzaghi wrapped up the victory with a third goal for Lazio after a delightful chip from 20 metres.
Lazio coach Roberto Mancini said he had only entered the field of play to try to calm his players.
"It all started after the first sending off, which I think was fair as it was an ugly foul. I didn't see the other incidents well.
"As for the scenes that followed, I was only trying to get my players away from the incidents," he said.
Perugia president Luciano Gaucci said the match was proof of bias against his club and described the referee as "incapable".
STRAIGHTFORWARD
It was a straightforward three points for Milan in Verona as Ukrainian Shevchenko continued his prolific season.
The striker put Milan in front on the stroke of halftime with a thundering header as he burst into the area to meet a pinpoint cross from Gennaro Gattuso.
Five minutes after the break Rui Costa found Shevchenko unmarked at the back post and as the Chievo defence stood claiming offside he smashed home Milan's second.
Empoli moved away from the foot of the table as they pulled off a 1-0 win at home to Parma with an injury-time goal from Pasquale Foggia. It was their first success of the season.
Ancona are now bottom after a 1-1 draw at home to Brescia.
