Mateo Rotegui's brace plus goals from Davide Zappacosta and Ademola Lookman without reply resulted in Thiago Motta suffering his first home defeat as the Bianconeri head coach.
Turkish teenager Kenan Yildiz was a surprise starter as he had recently experienced a stomach bug, and slotted into the midfield alongside Nico Gonzalez and Weston McKennie. Teun Koopmeiners was a substitute against his former side, and kept out-of favour Serbia striker Dusan Vlahovic company on the bench inside the Allianz Stadium.
There was a frenetic start, with the rain lashing down, as both sides were eager to dominate play by entertaining the crowd in Turin with end-to-end attacks.
The first chance to score fell for Atalanta on four minutes, when Ederson found Ademola Lookman down the left on a counterattack. Khephren Thuram managed to track back in time to make a decisive block to spare the blushes.
And four minutes later Thuram almost broke the deadlock. Kolo Muani cut the ball back to Thuram, who blazed his effort over the bar from the edge of the box,
Michele Di Gregorio did well to deny Lookman midway through the first half, and on 25 minutes disaster struck for the Bianconeri.
Martin De Roon;s free-kick was nodded down by Berat Djimsiti onto McKennie's arm, forcing the referee to blow for a penalty. There was a VAR review to determine whether Lookman had controlled the ball with his arm in the build-up.
Retegui opens floodgates
After Lookman’s recent penalty controversy in the Champions League, publicly critcized by his manager Gian Piero Gasperini, Retegui stepped up to take the shot. The Italian international, one of three Atalanta players on Juve's summer wishlist, made no mistake to fire low to the right of Di Gregorio
Atalanta slowed the game down, keeping hold of the ball, as they tried to negate any sort of Juve response. Although the hosts playing well in patches, their inconsistency made creating chances a struggle.
It looked like it was only a matter of time when Atalanta would double their lead late in the first half. Di Gregorio smothered a Djimsiti effort and made a spectacular one-handed save to deny Davide Zappacosta, Lookman hit the post and defensive midfielder Ederson fired his shot wide.
Motta's half-time team talk proved to be ineffective as Atalanta scored within the opening minutes after the turnaround. Lloyd Kelly's poor pass was intercepted by Marten de Roon to start the counter. Lookman's angled shot parried by Di Gregorio, Kelly blocked Retegui’s rebound effort with De Roon on hand to find the back of the net from 10 yards.
This second goal knocked the stuffing out of Juve, who started losing battles all across the pitch. The hosts were slow to react and were outplayed by energetic Atalanta.
Despite McKennie blasting his 50th-minute shot wide from the edge of the box, the Bianconeri faithful were fuming. Protests in recent weeks were followed by Sunday's chants ringing around the jam-packed stadium.
An audacious back-heel flick from Sead Kolasinac to Zappacosta bamboozling the Juve defence. Zappacosta’s finish then nutmegged Kelly on the way into the far bottom corner for an embarrassing goal to extend the lead by a three-goal margin.
Thousands of disappointed Juve fans headed for the exit, and missed the final goal. Dusan Vlahovic, who replaced Kolo Muani, slipped over in the center circle with Lookman latching onto the loose ball. His effort was deflected to wrong foot Di Gregorio at the near post for a 4-0 thumping win to keep Atalanta in the race for the Scudetto.
Boos greeted Motta and his troops at the final whistle, as they didn't show the bottle for a battle. Juventus last conceded four Serie A goals at home back in 2011, when Parma inflicted a 4-1 defeat
The Bianconeri fell nine points behind leaders Inter Milan, and a win for Lazio at home to Udinese on Monday would see Juve drop to fifth place and outside an automatic Champions League place.