Brazilian-born forward Amauri ended a barren four-match run in Serie A for Juventus on Sunday by scoring the only goal in a laboured 1-0 win at struggling Siena.
Amauri rose between two markers to head home a Diego free-kick in the 72nd minute to break the deadlock after the Turin side had struggled to pose a threat for much of the match.
Juve are third with 18 points from nine games, four behind Inter Milan and two shy of second-placed Sampdoria, after the leading duo beat Catania 2-1 and Bologna 4-1 respectively on Saturday.
Fiorentina, who started the weekend level with Juve, are three points further back after they lost 1-0 at home to Napoli.
Juventus had plenty of problems with the defensive wall erected by their Tuscan opponents and centre back Giorgio Chiellini headed their only decent chance of the first half wide.
But they reaped the maximum reward for raising the tempo briefly in the middle of the second half and Amauri's goal sank Siena to the foot of the table, putting more pressure on coach Marco Giampaolo.
"It was fundamentally important for us to get back to winning," Juve coach Ciro Ferrara, who made a number of changes to the side that beat Maccabi Haifa 1-0 in the Champions League on Wednesday, told Rai television.
"We managed to do that even though we had problems. I think it bodes well for Wednesday's match (against Sampdoria)."
Napoli's Christian Maggio ran on to a German Denis pass and poked in a late goal to hand Fiorentina their first home defeat this season and give Napoli their first away victory in 12 months.
They looked like they were set to go home with just a point when Fiorentina's Sebastien Frey pushed away Fabio Quagliarella's spot-kick 10 minutes from time.
Palermo climbed up to joint fourth alongside the Florence club with a 1-0 home win over Udinese secured by Cesare Bovo's deflected late volley.
Livorno moved off the bottom by beating AS Roma 1-0 away thanks to former Roma forward Francesco Tavano's 40th-minute strike to give new coach Serse Cosmi a win in his first game in charge despite having goalkeeper Alfonso De Lucia sent off in the 64th.
Roma's Mirko Vucinic had struck the post in the 56th minute having just messed up a glorious opportunity to equalise with the goal gaping.
AC Milan will be out to continue their recovery from a shaky start by building on wins over Real Madrid and Roma in their last two matches when they visit Chievo Verona in Sunday's late game.