Ante Rebic rescued a point for AC Milan to leave Juventus still searching for a first Serie A win of the season.
Rebic's header from a Sandro Tonali corner sees Juve slip into the relegation zone, sitting in 18th.
Alvaro Morata had given the hosts the ideal start, finishing a counter attack with a cooly-taken chipped finish.
Pierre Kalulu almost compounded Juve's woes after Rebic levelled, forcing Wojciech Szczesny into a close-range save that preserved a point for Juve.
The late drama leaves Massimiliano Allegri waiting for a first league win in his second spell as Juve boss after guiding them to five league titles in his first stint.
He has started his second tenure by overseeing one of their worst league starts for 60 years. It is only the fourth time in their history - after 1961-62, 55-56 and 42-43 - that Juve have failed to win one of their first four Serie A matches.
Morata, who inspired Juve to victory over Malmo in the Champions League in midweek, scored his third goal in three games to give the hosts the perfect start against an AC Milan side missing a host of key players, including Zlatan Ibrahimovic, Olivier Giroud and Davide Calabria.
Juve remained the most industrious before the break but failed to capitalise, with Croatian forward Rebic eventually earning Milan a hard-earned point that lifts them back to second in the table.