FC Barcelona prevailed 2-0 over English side Manchester City yesterday but scoring both their goals, a penalty by Lionel Messi and a late goal by Dani Alves, only after Argentinian defender Martin Demichelis was sent off eight minutes into the second half.
PSG, who were eliminated by FC Barcelona in the quarter-finals last season, thumped German outfit Bayer Leverkusen 4-0 in Germany but, unlike FC Barcelona, took the match by the scruff of the neck early on and led 3-0 at half-time with Zlatan Ibrahimovic scoring two of them.
The City and FC Barcelona clash turned in the 53rd minute when Demichelis brought down Messi, with replays suggesting the foul happened just outside the penalty area.
However, Swedish referee Jonas Eriksson thought otherwise and not only awarded the penalty but also sent off Demichelis.
City did not wilt and had their chances to pull level but instead were hit by a sucker punch at the end as the always dangerous Alves nipped in to slot home a sweetly-taken goal.
FC Barcelona midfielder Cesc Fabregas said it had been an important statement by his side in light of some remarks, especially by former Real Madrid and now Chelsea boss Jose Mourinho, who had said they were the worst FC Barcelona team of "many years".
"Well we are in the Spanish Cup final, top of the league and we won with a great performance tonight, so we must be doing something right," said the 26-year-old.
"Some people have been doing a lot of talking, nothing new there with one of them, and hopefully this will make them shut up for a few days."
Manchester City manager Manuel Pellegrini blamed Eriksson for tilting the game in FC Barcelona's favour.
"I think that the referee decided the game," he said. "Before the penalty there was the foul on (Jesus) Navas, when he (Eriksson) was three metres from the player, so he saw it without any problem.
"From the beginning I felt that the referee was not impartial to both teams. The penalty on Martin Demichelis was not a penalty -- it was outside the box."
PSG untroubled in Germany
While that match remained tight until the end, the other game was over as a contest by half-time as PSG overwhelmed a side that lost 10-2 on aggregate to FC Barcelona the last time they appeared in this stage of the competition two years ago.
Blaise Matuidi scored the opener and Ibrahimovic the other two, the second of those a scorching effort from outside the box.
The hosts' chances of at least getting a goal back decreased markedly when Bosnian international defender Emir Spahic -- who had been responsible for conceding the penalty that Ibrahimovic scored for his first goal -- was sent off for a second bookable offence.
PSG grabbed a fourth late in the game through recent signing Yohan Cabaye.
"We had a good start and when you are one goal up, it's easier, it gives you space," said Ibrahimovic.
"We had a good first half and continued to play our game after the break, when they played with one less, so it was a good day."
PSG coach Laurent Blanc, who is bidding to bring France only their second ever win in the competition with Marseille having won it in 1993, was delighted with the performance.
"I think we rediscovered the PSG of the first part of the season," said the former France national coach.
"They were hungry to build moves and to be clinical, things that we slightly lost our way in.
"Here we were all those things while maintaining our philosophy of how to play.
"We will savour this then get ourselves ready for the second leg in Paris in three weeks, which we have to win."