Juventus' 100 per cent start to the Serie A season was snapped by a battling Atalanta side who came from two goals down to earn a 2-2 draw against the champions.
A roller-coaster ride at the Stadio Atleti Azzurri d'Italia featured four goals and a pair of contentious VAR decisions as either side felt aggrieved by reviews made by referee Antonio Damato.
Federico Bernardeschi, making his first start for Juventus, opened the scoring for the visitors in the 21st minute, before supplying the assist for Gonzalo Higuain to make it 2-0 three minutes later.
Atalanta's fightback started when Mattia Caldara - on loan from Juventus - pulled a goal back shortly after the half-hour mark and at 2-1, Juventus had a Mario Mandzukic goal cancelled out following Stephan Lichtsteiner's foul on Alejandro Gomez.
The comeback was completed by Bryan Cristante, who scored the pick of the goals with a pinpoint second-half header, but Atalanta's efforts looked to have fallen short when Juve were given a controversial penalty late on for an Andrea Petagna handball, upheld on review.
But Etrit Berisha, at fault for the game's opening goal, denied Paulo Dybala from the spot to leave Massimiliano Allegri's side trailing the faultless Napoli at the top of the table.
Juventus had the better of the early going and went close after 14 minutes when Mandzukic knocked the ball down and into the path of Higuain near the penalty spot, but the Argentine's effort lacked the necessary power to beat Berisha.
Bernardeschi was in the thick of the action as Juve forged ahead, first by pouncing when Berisha spilled Blaise Matuidi's drive at his feet and poking the ball into the net from point-blank range.
The EUR40million signing from Fiorentina then threaded a pass into the box for Higuain, who shook off the challenge of Jose Luis Palomino and rifled the ball high into the roof of the net to double Juve's advantage.
Juventus looked to be heading for a comfortable outing until the 31st minute when Gianluigi Buffon failed to hold Gomez's free-kick and Caldara was on hand to side-foot the rebound into the corner of the net.
500 - Mattia Caldara has scored the 500th goal conceded by Gianluigi Buffon with Juventus (all competitions). Aim. #AtalantaJuve-- OptaPaolo (@OptaPaolo) October 1, 2017
Gian Piero Gasperini sent on Josip Ilicic, who swung in a dangerous cross that Jasmin Kurtic headed just wide as the home side pushed for an equaliser before half-time.
Higuain and Dybala linked up well as Juventus reasserted their grip on the game in the second half and the former fired a shot just over the crossbar shortly before the visitors had the ball in the net for a third time.
Dybala crossed for Mandzukic to head the ball down into the net after 57 minutes but Damato consulted the video and ruled the goal out due to a foul in the build-up by Lichtsteiner, who was shown a yellow card for elbowing Gomez in the face.
Lichsteiner was swiftly withdrawn by Allegri as his spat with Gomez rumbled on and, having survived the scare, Atalanta sprung into life to draw level.
After he was booked for a foul on Lichtsteiner, Gomez found his composure to deliver a neat cross, which Cristante rose to meet with a powerful header into the corner of the net in the 67th minute.
Atalanta were fuming when Juve were awarded a penalty in the 83rd minute, and Damato saw fit to stick with his decision, despite viewing replays which appeared to show the ball hitting Petagna's shoulder.
But Dybala's spot-kick was saved by Berisha, who dived down to his left to push the ball away and preserve a passionately celebrated point for the hosts.
KEY OPTA STATS
- Juventus had not failed to win from a two-goal lead since February 2014 against Verona.
- Atalanta have lost only one of their last 15 home league games (W9 D5).
- Paulo Dybala has missed his first penalty in Serie A, on the 14 taken.
- Gonzalo Higuain has scored seven goals against Atalanta: he scored more only against Lazio (12) in Serie A.
- All the five Bryan Cristante's goals in Serie A with Atalanta have been headed and assisted by Gomez.