It isn't often you see Barcelona look shocked in the Champions League.Luis Enrique's men knew they were in for a potentially tough night before a whistle had even been blown at the Parc des Princes but having beaten Paris Saint-Germain three times last season, they were still favourites to progress.And yet the French champions completely dominated the early stages of Tuesday night's encounter.Even with the likes of Lionel Messi, Luis Suarez and Neymar on the field the Catalans really struggled to grab a foothold on proceedings and were eventually made to pay.After Edinson Cavani and Adrien Rabiot wasted the game's first big chances it was up to Angel di Maria to find the breakthrough - and he did it in style.Messi has been in truly supreme form from free-kicks since the turn of the year and you'd like to think even he would have appreciated his Argentine compatriot's effort.Just outside the Barcelona box, Di Maria stepped up to produce a curling strike into the right corner.As you can see in the video below, Marc-Andre ter Stegen had absolutely no chance of keeping it out.Not a bad way to celebrate your 29th birthday is it?Here's how fans reacted to the goal on Twitter:

Messi did get the chance to grab a goal back shortly after with a free-kick of his own but unlike Di Maria, couldn't get past the wall.

And things got even worse for Barca before half-time when Marco Verratti robbed Messi in his own half to play Julian Draxler through to grab a second.

Although there is still a second leg to play, you don't fancy Barcelona to survive the first at this rate.