Udinese went top of Serie A with a 2-1 win at home to Chievo as AC Milan were held to a 2-2 draw at Bologna on Sunday.
Juventus can reclaim the lead on Monday when they travel to Roma.
Captain Antonio Di Natale and Dusan Basta gave Udinese a 2-0 lead before Alberto Paloschi's late consolation kept things interesting right to the end.
Udinese now lead by a point from Juventus with Milan and Lazio, 3-2 winners at rock bottom Lecce on Saturday, a point further back.
"It's great, it's wonderful, it's a magical moment and we'll try to keep it going as long as possible," said elated Udinese coach Francesco Guidolin, whose side finished fourth last year, his first with them.
"Udinese have done well in recent years but matching the last year and a half would be difficult."
The hosts had a scare when Chievo's Luciano found himself 10 yards out and in front of goal but he blazed his volley wide.
Up the other end Ghana midfielder Kwadwo Asamoah broke forward but dragged his shot wide while Morocco centre-back Mehdi Benatia fired in an effort that was tipped over the bar by goalkeeper Stefano Sorrentino.
In the second half Di Natale was denied twice in quick succession by desperate defending.
The striker was about to knock home the rebound after Sorrentino saved Mauricio Isla's shot but Boukary Drame slid in to block his effort.
Then moments later Nicolas Frey hacked his back-flick off the line with Sorrentino beaten.
But Udinese got the goal they deserved when Chievo finally cracked under the pressure and Di Natale headed home Isla's cross.
Dusan Basta seemed to have settled the affair with a stooping header from a corner but Alberto Paloschi curled home a shot from outside the box eight minutes from time to keep Udinese's fans on the edge of their seats.
In Bologna it was a controversial tale of penalties given and not as Marco Di Vaio and Alessandro Diamanti scored for the hosts with Clarence Seedorf and Zlatan Ibrahimovic, from the spot, replying for the champions.
Bologna were off to a flying start when Di Vaio broke the offside trap on 11 minutes, running onto Diamanti's long ball and lobbing the onrushing Marco Amelia.
The lead lasted only five minutes, though, before Kevin-Prince Boateng beat two players and slipped the ball to Seedorf, who smashed a stunning strike from 20 yards into the top corner.
Bologna were showing no signs of either fatigue from their extra-time Italian Cup defeat to Juve in midweek or being intimidated by illustrious opponents.
Di Vaio had a shot from an angle that whistled just past the corner of post and bar.
A nice lobbed pass from Boateng sent Ignazio Abate running into the area but his volley was saved by Jean-Francois Gillet.
Milan then had a lucky escape on the stroke of half-time when Seedorf appeared to handle in the area but the referee gave nothing.
Milan coach Massimiliano Allegri admitted certain decisions had gone his side's way.
"Seedorf touched it with his arm, that was a penalty," he said.
Bologna had the bit between their teeth and Di Vaio's deflected shot beat Amelia but hit the post.
Milan were then awarded a penalty for a foul on Ibrahimovic who duly slotted home from 12 yards, although there appeared very little contact between him and Andrea Raggi.
"The defender kicks and he (Ibra) throws himself down, there's no point denying the evidience," added an honest Allegri.
And yet 60 seconds later Diamanti turned inside Thiago Silva and fired home.
Milan then also had a shout for a penalty for handball against Archemide Morleo from Ibrahimovic's point-blank cross but that wasn't given.
"The refereeing mistakes weren't one-way," was Allegri's final take on the decisions.
In other games Atalanta and Catania drew 1-1 while it remained goalless between Cagliari and Parma.