Medhi Benatia opened the scoring in the 29th minute and Antonio Di Natale added a second from the penalty spot 18 minutes from time as unbeaten Udinese recorded their third victory in five games this season.
The Friuli club, who finished fourth last season, are now a point clear at the summit, although Juventus can join them on 11 points if they beat AC Milan later this evening.
It was struggling Bologna who started the better today though and Alessandro Diamanti had two chances in the opening 16 minutes, firing the first wide before sending the second over the bar following a superb assist from Henry Gimenez.
Udinese finally gave the visiting defence something to worry about in the 26th minute when Di Natale tested Bologna goalkeeper Federico Agliardi from the edge of the box, and three minutes after that the home side moved in front.
Defender Benatia was the goalscorer, turning in a corner at the near post for his first goal of the season.
Benatia then proved his worth at the other end of the pitch with a brilliant tackle to deny Marco Di Vaio, who was one-on-one with Samir Handanovic to beat.
Following that scare, Udinese set about trying to increase their advantage and, after Pablo Armero and Di Natale had tried their luck from long range, the hosts thought they had doubled their lead on the stroke of half-time when Dusan Basta tapped in after Di Natale's shot had come back off the post.
However, that effort was ruled out due to a debatable offside decision against Basta.
Udinese continued to push forward after the break and Di Natale fired an effort just wide before Bologna started to come back into the contest as they sought to avoid a fourth defeat in five games.
Gabi Mudingayi shot wide after ignoring unmarked team-mate Federico Casarini before Diamanti brought a great diving save out of Handanovic.
Bologna could not get back on terms during that spell however and Udinese were soon back on the attack and celebrating their second goal.
Gabriel Torje was denied at close range by a superb save from Agliardi but the visiting custodian was left with no chance in the 72nd minute when Di Natale slotted home from the spot after Diego Perez had fouled Armero.
Both sides had chances to net after that, with Di Natale, Mauricio Isla and Basta going close for the home side and Diamanti twice threatening late on, but Udinese had done enough for the points.