Ahead of Saturday's Champions League final between the two sides, some Barca stars feel that Ronaldo's departure to Real Madrid in 2009 has improved the United squad.
"Their team isn't as direct as before; they like to have the ball," Xavi said.
"I don't know if that's because of Cristiano Ronaldo or not, but they move around as a unit now."
"Many great players come and go and that has allowed them to remain at the top for so long."
Dani Alves said there was an air of unpredictability about the Red Devils without Ronaldo.
"They have formed a more balanced group and they are stronger than they were two years ago."
Whilst Andres Iniesta added: "They have grown as a team. They are dominating in England and now they are fighting for the Champions League.
"Cristiano Ronaldo has left, but apart from that I don't think they have made big changes and they are always competitive."