Losing at Serie A leader Inter Milan can be forgiven, a defeat at home to relegation-threatened Udinese less so.
Juventus were booed off the field by their fans on Monday (Tuesday AEDT) after a 1-0 loss at home to Udinese left their title hopes in tatters.
Massimiliano Allegri's side, who lost 1-0 at league leaders Inter Milan last week, stayed seven points behind the Nerazzurri, who also have a game in hand.
Juventus are only one point above third-placed AC Milan.
Lautaro Giannetti's first Serie A goal was enough to hand Udinese only their second win in 14 matches and lift them three points above the drop zone.
Juventus forward Arkadiusz Milik missed a number of gilt-edged chances to equalise, and also had a goal disallowed.
Milik was returning from a suspension and started in place of in-form forward Dusan Vlahovic, who was out with a muscle problem.
Juventus started brightly but it was Udinese who took the lead in the 25th minute.
Thomas Kristensen nodded on Lazar Samardzic's free kick and Juventus defender Alex Sandro's attempted clearance was straight at Giannetti, who fired it in from close range.
Milik could have levelled almost immediately, but he mishit a cross and sent it woefully wide of the target from point-blank range.
The Poland forward headed another cross straight at Udinese goalkeeper Maduka Okoye shortly before half-time.
Juventus were jeered off the field at the break, and matters didn't improve much after the interval.
Milik did get the ball in the back of the net in the 58th minute after Adrien Rabiot had nodded on a corner, but it was ruled out because Federico Chiesa's corner delivery had crossed the byline.
Australian Associated Press
