Celtic were swept aside by a rampant Paris St-Germain, who hit seven in the Parc de Princes.
The visitors opened the scoring in the first minute through Moussa Dembele, but were then swamped.
Neymar scored twice, then created the third for Edinson Cavani, before Kylian Mbappe struck before half-time.
Marco Verratti, Cavani and Dani Alves scored in a five-minute blitz in the second half to compound Celtic’s misery.
The victory was PSG’s biggest win in the Champions League, and a chastening night for the visitors, who lost 5-0 to PSG at home earlier in the group.
The Scottish champions still have the advantage in the race to finish third in Champions League Group B – and qualify for the Europa League – with bottom-placed Anderlecht losing 2-1 to Bayern Munich.
The Parc des Princes was a blaze of colour before kick off, with the home fans as noisy as they were no doubt confident in their team. After all, PSG’s record at home is nothing short of remarkable: they had yet to conceded a goal in this season’s Champions League group stages.
Yet this game was less than a minute old when Celtic spoiled that particular statistic.
Alves’ poor backpass resulted in a corner for Celtic, and the visitors took full advantage. Olivier Ntcham played a low ball to Dembele at the edge of the area, and the striker clipped a shot over PSG goalkeeper Alphonse Areola.
That was enough to send the travelling fans into raptures, but PSG were soon back on level terms.
Adrien Rabiot showed his class in midfield, intercepting Scott Brown’s wayward pass then shrugging off the Celtic captain before sending Neymar surging into the Celtic penalty area. The worlds’ most expensive player showed his worth and his pace, as he beat Craig Gordon in the Celtic goal with a low shot.
As the French side moved up through the gears, Celtic’s cause wasn’t helped when they lost defender Mikael Lustig just 12 minutes in. The Swede pulled up injured and was replaced by midfielder Nir Bitton.
It wasn’t long before PSG’s talent told. Neymar’s neat one-two with Verratti on the edge of the box was finished off brilliantly by the Brazilian. The home side were ahead, and you sensed more was to come.
Celtic were not coping well the waves of PSG attacks. Cavani took advantage of poor Celtic defending and fired in another, his 20th of the season, after Neymar turned the ball across the face of goal with his upper body.
With 28 minutes on the clock, you feared for Celtic. PSG were sublime, Celtic were struggling. The visitors’ early goal seemed a long time ago.
And there was more punishment for slack Celtic defending as half-time approached. A free-kick wasn’t cleared, and Mbappe was left unmarked to beat Gordon with a firm finish back across the goalkeeper
Celtic minds were scrambled, but the half-time interval offered some brief respite. The visitors seemed to make the most of regaining their senses, and Brown delivered a clever pass to Dembele early in the second half, but the Frenchman snatched at his shot.
Celtic’s enterprise was short lived, though, as PSG continued their assault on the visitors’ goal.
Their persistence paid off, as Verratti slammed the ball past Gordon from the edge of the area.
PSG were relentless, and Cavani added his second of the night four minutes later with a stunning volley from a wonderful Javier Pastore cross.
Celtic’s pain wasn’t over. Alves delivered the final blow, gathering the ball 20 yards out then whipping a shot beyond Gordon’s reach and high into the far corner of the net.
It was a crushing night for the visitors, one they will hope to quickly forget.