Milan - Cristiano Ronaldo's arrival in Turin last summer had been hailed as a masterstroke on the part of the Italian giants in their bid to end their 23-year wait to lift the Champions League title.
The Portuguese superstar had won five Champions League titles with Manchester United and Real Madrid and scored a record 121 goals in the competition.
But instead the Serie A giants are now facing the possibility of an early exit after falling 2-0 in their last 16, first-leg clash against Atletico Madrid on Wednesday night.
Once again the 34-year-old Ronaldo did not have a return to the Spain he had dreamt of.
The former Real Madrid player was sent off in his first European game for Juventus in Spain last September against Valencia.
This time he was whistled and mocked by home fans, and delivered a performance far below expectations for a player Juventus had paid €100 million for.
Ronaldo replied by waving five fingers at the crowd, telling journalists: "I've got five Champions League trophies and Atleti have won zero."
But his hopes of a sixth and first with Juventus diminished as he was stifled from the outset by Atletico's backline.
"It was a tough night," said Ronaldo, who has scored 22 goals against Atletico.
Ronaldo's best contribution was an early, driven free-kick from 30 yards, that had to be pushed over by Jan Oblak.
Atletico were celebrating at the final whistle as goals from Jose Gimenez and Diego Godin, with a shot that deflected into the net off Ronaldo, put Diego Simeone's side within sight of the quarter-finals.
Italian sports daily Gazzetta Dello Sport was scathing of Ronaldo who received just 4.5 out of ten as "the worst" player on the pitch, with Polish goalkeeper Wojciech Szczesny Juventus's "best" with 6.5.
"CR7, you can save this Juve," urged Turin daily Tuttosport looking ahead to the second-leg tie in the Allianz Stadium on May 12.
Coach Massimiliano Allegri was also in the firing line after what Gazzetta dello Sport termed "a Waterloo of play and attitude".
The Juventus coach admitted his side got it wrong particularly in the second half when they were rescued twice by VAR.
"They don't give you chances," said Allegri. "They make you play badly."
The Italians have also had setbacks with midfielder Sami Khedira recovering from a heart problem with defensive duo Leonardo Bonucci and Giorgio Chiellini just back from injury.
Juventus are unbeaten in their pursuit of an eighth straight Serie A crown. They are 13 points ahead of nearest rivals Napoli after 24 games.
But their domestic domination has been broken. At the end of January they lost at Atlanta to end their bid for a fifth straight Coppa Italia crown.
Juventus recruited Ronaldo for a treble of Champions League, Serie A and Coppa Italia crowns.
With their most important challenge now requiring they score at least twice against a team that specialises in defence, Juventus share prices went into free fall, losing nearly 10 percent on the Milan stock exchange on Thursday morning.
"20 days. 20 days to be ready for a challenge to live, and win, all together. Until the end," urged Allegri on Twitter.
In between, Juventus have three Serie A games, including a clash with their closest challengers Napoli on March 3.
Before then they travel to struggling Bologna on Sunday.
By the time Juventus play, Ronaldo could have lost his place as the top scorer in Serie A.
Ronaldo has 19, two more than AC Milan's new Polish signing Krzysztof Piatek who has scored four goals in as many games since moving from Genoa. He is in action on Friday as Milan host Empoli.
Milan will be looking to consolidate fourth place which is the final Champions League berth, ahead of the pursuing pack of Roma, Atalanta and Lazio.