Barcelona needed ... the ball around elegantly and PSG had no attacking outlet, with Cavani miles from goal whenever he got the ball on the counter. But the PSG game plan was working.

And a key year in which everything intensified was 2017. Follow the link below to dive into the rivalry. GO FURTHER Messi and Neymar help explain it, but Barcelona and PSG tensions go deeper still ...

Back in March 2017 they had won the first game 4-0 ... According to PSG there was also a fourth crucial factor – the referee. No one could sleep on the flight back to Barcelona from Paris.