Juve on brink of title after comeback win

Juventus entered the game in Turin with a four-point lead over chasing Napoli and just three matches of the season to play, but the hosts fell behind to a first-half penalty from Bologna's Simone Verdi.

However, an own goal from visiting defender Sebastien De Maio on 52 minutes allowed Juventus to draw level before Costa supplied Sami Khedira and then Paulo Dybala for two quick goals to seal the victory.

Juventus's six-year reign in Italy looked under threat a fortnight ago when Napoli snatched a dramatic 1-0 win over Massimiliano Allegri's side, but last week's late heroics in Milan left the Turin giants once again in charge of the title race.

After Juventus threatened through Gonzalo Higuain and Alex Sandro, Bologna grabbed a surprise lead when Lorenzo Crisetig pounced on a sloppy pass from Gianluigi Buffon and was fouled in the area by Daniele Rugani.

Italy striker Verdi calmly rolled the spot-kick past Buffon to send Bologna ahead on 30 minutes and quieten the expectant Allianz Stadium.

The introduction of Brazilian Costa for Blaise Matuidi at half-time triggered an electrifying response from the home team and Juventus hit back when De Maio sliced an attempted clearance into his own net.

Bologna nearly regained the lead after a defensive lapse left Emil Krafth alone in front of Buffon, the veteran keeper producing a marvellous fingertip stop to divert the ball onto the upright.

- Costa makes his mark -

That served as a wake-up call for Juventus who went ahead on 63 minutes as Costa's deep cross floated over a flapping Mirante and was stroked home at the far post by Khedira.

Another surging Costa run down the left produced his side's third goal six minutes later when his low cross was brilliantly dispatched first-time by Dybala for his 22nd goal of the season.

Juventus can clinch the title on Sunday if Napoli lose to mid-table Torino, otherwise victory in one of their final two matches -- away to Roma and at home to relegated Verona -- would also be enough.