Celtic needed less than a minute to do what no other Champions League team has managed this season, by scoring a goal against title favorite Paris Saint-Germain.
It then paid a heavy price for its insolence.
PSG hammered seven goals past the Scottish champions as Neymar, Kylian Mbappe and Edinson Cavani unleashed the full might of the French side's attack in a devastating 7-1 rout on Wednesday.
On a night when PSG set a new Champions League record with 24 goals in the group stage, with one game to spare, the hosts conceded within seconds, but struck back with a vengeance. Neymar scored twice and set up another goal as PSG extended its perfect record in Group B to five games.
PSG leads the group with 15 points, three more than Bayern Munich, which won 2-1 at Anderlecht. Both PSG and Bayern were already guaranteed a spot in the knockout stage and will now battle for group supremacy when they meet in Munich on Dec. 5.
"When we play like this, it's tough for the others," said Cavani, who also scored twice and took his career tally for the club to 151 goals.
Celtic's dream start at the Parc des Princes followed a corner. Moussa Dembele, who came through the PSG academy, collected a pass from fellow Frenchman Olivier Ntcham on the right side of the box and unleashed a first-time shot that took a slight deflection and surprised goalkeeper Alphonse Areola.
PSG recovered quickly and leveled within minutes after Adrien Rabiot intercepted near the halfway line. The France international rushed toward the goal and set up Neymar on the left. The Brazil star controlled the ball with a fine touch and slotted home with an angled shot.
PSG was shaky in midfield, losing possession several times, but a moment of brilliance from Neymar put PSG ahead in the 22nd minute. The former Barcelona player received the ball in front of the box, played a quick one-two with Marco Verratti, avoided a tackle and beat goalkeeper Craig Gordon with a low shot.
PSG was unstoppable after that, and pegged back Celtic in its own half for the rest of the match. Cavani, the top scorer in Europe's major leagues this season, made the most of Celtic's poor defending to make it 3-1 with a simple tap-in after Neymar headed down the ball in his path.
Celtic's defensive inadequacies were again on display in the 35th when Mbappe was left unmarked on the right side of the box and gave Gordon no chance with his precise shot.
The pace slowed down in the second half but PSG continued its domination with rapid attacks that had the Celtic back four in trouble. Following a series of half-chances, Verratti added his name to the score sheet, Cavani scored with a fine volley at the far post and Dani Alves completed the rout with a floating shot past Gordon in the 80th minute.
"Sometimes you just have to take your hat off in terms of the quality. It's a top team with top players," Celtic manager Brendan Rodgers said. "Our players gave absolutely everything, they ran themselves into the ground. They fought, we got a great start to the game, we showed confidence in the game, but we made mistakes that let them back into it."