Beckham was back at Old Trafford on Tuesday night in support of best pal Gary Neville at his testimonial match along with other graduates from the famous Class of '92 Youth Cup-winning side.
The midfielder said it was great to be back in Manchester to see some old friends and he hopes to see them lift the trophy at Wembley on Saturday.
"They're coming up against one of the best sides in the world but this is the biggest club in the world. If anyone can beat Barcelona with the talent they've got in their side, it's Sir Alex Ferguson and Manchester United," Beckham told MUTV.
"I know how passionate Barcelona are and how great they are at playing the game, but United are a top side.
"It's going to be such a great occasion. Let's just hope United can do it."
Reflecting on his reunion with his former team-mates, Beckham added: "It was great. I haven't been on a pitch with them for almost 10 years.
"To be out there again on this field in front of this crowd with Sir Alex Ferguson as manager was a great occasion.
"Tonight was all about Gary. He got an amazing send-off from the fans but we all knew, even before tonight, how much they love him and how much he means to this club. He'll always be a part of this club and its history."