United looked to be heading out of Europe to Spanish opposition again when Robert Lewandowski’s first-half penalty put Barca 3-2 up on aggregate and in control at Old Trafford.
But a fine revival saw Fred equalise after only 82 seconds of the second half before half-time substitute Antony sent home fans wild with a 73rd-minute strike to seal a 2-1 win on the night and a 4-3 victory on aggregate.
Victory, which sends United through to the last 16, sees them still competing on all four fronts and is the perfect tonic ahead of Sunday’s Carabao Cup final against Newcastle.
Barca are runaway leaders in LaLiga, which gives Ten Hag belief his side are a match for anyone in Europe.
“It was a magnificent night,” he said. “I think it is brilliant when you can beat Barcelona, eight points ahead of Real Madrid in LaLiga and we have seen in this week Real Madrid playing.
“We have the potential to beat the big teams, we have shown we can beat City, we can beat Arsenal, we can beat Liverpool. If we do the right things, if we follow the rules, if we follow principles and show discipline and team spirit, I think this team can achieve a lot.
“You need a strategy to build that but also you need results to get that strong belief. I think this is another step because when you can beat Barcelona – one of the best teams in this moment in Europe – your belief can be really strong because then I think you are able to beat anyone.”
It was a big moment for Antony, who was introduced at half-time, following recent criticism for his performances.
But his arrival helped change the game and Ten Hag knows what he brings to his side.
“I know he can deal with it,” the Dutchman said. “He is brave, he is fearless, so I think what he brought in the second half was what we needed, running in behind and dribbles and his goal.
“He is brave and will go for it and when he has the opportunity he will strike. He brings so much to this team.”
At half-time Barcelona had one foot in the last-16 draw as they controlled the first half, but only had Lewandowski’s penalty to show for it.
They were unable to match United’s intensity after the break, but boss Xavi did not leave too disappointed.
“I think we lacked that calm and patience, we started the second half really badly, we were dominating the game and controlling it,” he said.
“We needed more more patience and more game management, we lost some duels and those finer details in the second half.
“We could have been more intense, we have lost a couple of duels, but in my point of view we lacked a little bit in our game. We were without Gavi and Pedro and in the second half that is where you saw the difference.
“In general we can be proud with how we have competed and shown our face against a really big side. It is a shame because we had an excellent first half. Now we need to concentrate on the league and cup.”
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