The Red Devils are readying themselves for another epic European encounter having disposed of Ligue 1 giants Paris Saint-Germain in the last 16.
That contest pitted Smalling and Co against the likes of Kylian Mbappe and Angel Di Maria, but they are delighted to be facing more global superstars in the last eight.
“We were warming up on the bikes in the gym [when the draw was made],” Smalling told Inside United.
“Normally we do 10 minutes on the bike and then we do some gym activation, but I think we stayed on the bikes for maybe 20 minutes just because we saw the draw was on the TV.
“We were all excited. As soon as it came out, we were all happy. We cheered and then we got on with training. But at least we knew who was in front of us.
“When the draw was made, you think, ‘I want to play against teams like this'. I was injured or just coming back from being injured for the first game [of the last 16 against PSG], so it was nice to be able to test yourself against the best, and I think PSG are one of the best teams in the world.
“Mbappe is probably one of the most in-form strikers in the world as well. I love to challenge myself against the best and that’s the good thing about this club: you’re always playing against the best because you’re getting a lot further in competitions.”
Challenges do not come much bigger than Barcelona and Messi, but Smalling says he is looking forward to facing a five-time Ballon d’Or winner.
He added: “I’ve not played against him competitively, personally, but in friendlies and pre-season we have.
“That’s someone else who I’m looking forward to playing against and hopefully minimising as many chances as possible, because we know what a world-class player he is. But it’s not just him; I think they’re a world-class team.
“We need to make sure that whatever game-plan we have – just like PSG – that we stick to it and everything falls into line. We know that we can give any team a right go.”
A meeting with Barcelona is the latest in a long line of tough assignments to have been handed to United this season, with the Red Devils having already faced Arsenal, Chelsea and Wolves in FA Cup competition and Juventus – who now boast Cristiano Ronaldo on their books - in the Champions League group stage.
“All our draws this season – be it FA Cup or Champions League – we don’t have the easy draws, and we thrive off playing big teams like that,” said Smalling.
“After the PSG game, we know that we can go away to the big teams and get results. We’re just looking forward to it. Let’s take it on.”