Erik ten Hag suggested that the "pressure" got to referee Maurizio Mariani after he failed to spot what the Manchester United manager believed was a clear red card offence committed by Barcelona defender Jules Kounde during the 2-2 draw at Camp Nou.

United were leading 2-1 in the first leg of their Europa League round-of-32 tie when Marcus Rashford went down under a challenge from Kounde as he looked to run through on goal.

Mariani waved play on before booking Ten Hag for his protests and afterwards the Dutch manager slammed the Italian official's decision.

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"If I make a point that has a big influence on this game and at this ground, at 2-1, it was a clear foul on Marcus Rashford," said Ten Hag.

"We can discuss if it's inside the box or outside the box, but definitely, it's a red card.

"I asked the referee why. So he said it was outside the box and it was no foul. And the linesman and referee were in a very good position to see and I think we had VAR. I think it's not good, it was a really bad decision. I can't understand.

"Maybe they were pressed by the pressure Barca made. It's a big influence, not only on this game but in this round, and referees can't make such mistakes."

Despite scoring his 22nd goal of the season and setting up the second through a Kounde own goal to put United in front, Rashford was also left furious at the decision not to flag for a foul after the collision with Kounde.

"I haven't watched it back, but I don't understand why the linesman or the referee thinks I am going down there?" Rashford told BT Sport.

"I have touched it past him, my foot is in front of the ball and he hits my leg. It's clear contact and was 100 percent a foul."

Barca coach Xavi Hernandez also fumed at the officiating for not awarding his side a penalty for a handball by Fred late on.

The ball struck the Brazilian midfielder's arm inside the area in the final 10 minutes but neither the referee nor the VAR deemed it sufficient to signal a spot kick.

"It's a penalty, for me, a really clear penalty," Xavi said in a news conference. "The position [of Fred's arm] was not natural. It's crystal clear. It happened in Milan in the Champions League [against Inter] and now here. I don't know what we have to do to get one. It's incredible it was not given."

United fought back from going a goal down to Marcos Alonso's 50th-minute opener to lead 2-1 before Raphinha equalised in the 76th minute for Barcelona. It will make United favourites to progress from the tie ahead of the second leg at Old Trafford next week but Ten Hag suggested his team should be heading back to Manchester with a significant lead.

"We created many chances and it's a disappointment that we didn't score them. We should have scored a minimum of four goals," he added.

"I think we dictated the game, apart from maybe 15 minutes in the first half, we had some difficulties, but in the rest we were dictating the game and we had so many chances."

Information from ESPN's Sam Marsden contributed to this report.