Two goals from Angel Di Maria and one apiece from Julian Draxler and Edinson Cavani gave Paris Saint-Germain an unexpected and potentially unassailable 4-0 lead against Barcelona in their Champions League round of 16 first leg tie.
Former Sevilla coach Unai Emery, a three-time Europa League winner, was appointed to improve upon PSG's record in the Champions League and the Spaniard has them on course for the quarterfinals courtesy of two goals in each half from a side playing without the influence and experience of Thiago Silva and Thiago Motta.
PSG had the better of the early exchanges with Blaise Matuidi and Adrien Rabiot forcing Marc-Andre ter Stegen into saves, before Di Maria scored an 18th-minute free kick to break the deadlock.
On the counter-attack Barcelona came close to an equaliser when Neymar picked out Andre Gomes' excellent run down the right wing, but his shot was comfortably saved by Kevin Trapp in the PSG goal.
But it was PSG who struck next, in the 40th minute when Lionel Messi was robbed of possession in midfield. Draxler played the ball inside to Marco Verratti who drove forward before picking out his German teammate to finish coolly past Ter Stegen from the right-hand side of the penalty area.
Ten minutes into the second half Di Maria added a third as PSG hit Barca on the break with great effect, the former Real Madrid man curling a left-footed shot into the top corner to leave Barcelona in real trouble ahead of the second leg.
And then, with Di Maria and Verratti both substituted, Cavani took advantage of more sloppy defending from Barca to add a fourth in the 71st-minute from close range after excellent work from Thomas Meunier.