Miralem Pjanic brought out his free-kick expertise to maintain Juventus' five-point advantage over AC Milan at the top of Serie A with a 2-1 win at Chievo.

Juve lost Andrea Barzagli to an early injury but slowly cranked up the pressure towards the end of a bruising first-half, before Mario Mandzukic broke the deadlock in the 53rd minute.

After playing a 100th Champions League match for Juve against Lyon in midweek, Gianluigi Buffon strode out for a 600th appearance in Italy's top flight at the Stadio Marc'Antonio Bentegodi, but the 38-year-old was beaten by a 66th-minute penalty from fellow veteran Sergio Pellissier.

Parity only lasted for nine minutes as Pjanic took advantage of prime position just outside the Chievo box to send a sumptuous strike flying into the top-right corner – the Bosnian's fourth in Juventus colours.

AC Milan's victory by the same scoreline at Palermo means Massimiliano Allegri's defending champions needed the win to preserve their cushion at the summit, although Roma will close to within four points if they beat Bologna in Sunday's late kick-off.

There was an early setback for Juventus when their veteran former Chievo defender Barzagli landed awkwardly defending a first-minute corner and appeared to injure his shoulder.

He left the field on a stretcher to a warm ovation from the home supporters, meaning Leonardo Bonucci's return from a thigh problem would be a more extensive substitute outing than Allegri envisaged.

Gonzalo Higuain burst into space down the left in the 11th minute but Chievo streamed back in numbers and shots from the Argentina striker and Juan Cuadrado were blocked.

Such tireless workrate was a prominent feature from Rolando Maran's men early on and midway through the half Nicolas Spolli powered a header narrowly wide from their latest attacking set-piece.

Mandzukic almost netted a superb opener for Juve in the 28th minute as he collected Pjanic's raking crossfield pass, lobbed the ball over Spolli but volleyed beyond the crossbar.

The Croatia international then headed a more straightforward chance wide, Cuadrado flashed a long-range drive just past the post and Chievo goalkeeper Stefano Sorrentino stood firm to deny Higuain at close quarters and keep the deadlock intact at the break.

Chievo looked to reassert themselves as an attacking force in the opening stages of the second period but they were ruthlessly punished for ceding possession in their own half after 53 minutes.

Defender Massimo Gobbi slipped and gave the ball away, with Cuadrado alert to thread a perfectly weighted throughball for Mandzukic to clip a low finish beyond Sorrentino.

Higuain rounded Sorrentino after the hour but Dario Dainelli got back to scramble behind and Chievo made the most of that escape.

Buffon had been a virtual spectator on his landmark appearance but reacted magnificently in the 64th minute, saving low down to his left when Lucas Castro smashed a loose ball goalwards before Rolando Maran's men levelled from the spot two minutes later.

Stephan Lichtsteiner played Pellissier onside and brought the veteran striker to ground as he bore down on goal.

Chievo's record appearance-maker and goalscorer picked himself up to coolly send Buffon the wrong way and mark his first start since September with a maiden Serie A goal this term.

But Pjanic imitated Pellissier in drawing a foul - Spolli the guilty party - and stepped up to score, stealing the points in picturebook fashion.

Juve should have added a third in the closing minutes, with Stefano Sturaro blazing wastefully over and the excellent Cuadrado slotting wide at the end of a spellbinding solo run, but there were no more alarms at the other end.