Barca were furious with Marciniak throughout the second-leg as Inter won 4-3 in extra-time to reach the final 7-6 on aggregate.
Marciniak awarded an Inter penalty for a foul by Pau Cubarsi on Lautaro Martinez. He also overturned a penalty call for Barca's Lamine Yamal, as VAR insisted he was fouled outside the box by Hakan Calhanoglu.
Barca were later aggrieved over Inter's equaliser at 3-3 over an apparent foul by Denzel Dumfries on Barca youngster Gerard Martin in the lead-up to Francesco Acerbi's goal.
“This isn’t the first time this has happened to us with this referee, and I think UEFA should look into it. There are things that are hard to explain," Barca midfielder Pedri told El Partidazo de Cope.
“There were many situations. Every 50/50 went their way, and on the penalty on Lamine, which was later called a free-kick, he didn’t give Mkhitaryan a yellow card, which would’ve been his second.”
"We all know what happens with his referee"
Barca defender Eric Garcia also stated: "I have come to Inter Milan's stadium three times and things always happen that are beyond our control. We all know what happened with this referee when we came here last time. But it's no excuse, they have scored six goals against us."
And in his post-match media conference, Barca coach Hansi Flick stated, "I don't want to talk too much about the referee, but every decision that was 50-50 went (Inter's) way.
"I am disappointed, but not with my team. They tried everything. It's the way it is. We are out, but next year we will try again to make the fans happy.
"It makes me sad... My team did an excellent job. I don't like talking about the referee... I've told him what I think, but I'm not going to say it here what I've said."