Gerard Pique made 23 appearances for Manchester United before joining Barcelona in 2008
Barcelona defender Gerard Pique says Manchester United are the "biggest team in England" as he prepares to face his former club in the Champions League.
United host Barca at Old Trafford in the quarter-final first leg on Wednesday.
Pique spent four seasons at United after joining as a 17-year-old in 2004.
"They have always been the biggest team in England," he said. "All big sides go through good times and bad times, and there are periods of transition."
The Champions League represents United's only chance of silverware this season with the Red Devils currently sixth in the Premier League, 21 points behind leaders Liverpool.
They have not won the Premier League title since Sir Alex Ferguson's final season in charge in 2013, with rivals Manchester City lifting the trophy twice in that time.
Despite their lack of a recent league title, Pique still believes United are the team to beat in the Premier League.
"I think it's the biggest team in England and they've shown that by the national titles they've won," said the 32-year-old.
"The period of Sir Alex Ferguson at Manchester United was the best one and they'll continue to be a big side."
Pique made just 23 appearances at Old Trafford before returning to boyhood club Barcelona in 2008. Despite his lack of game time, the Spaniard says he learnt a lot during his time in Manchester.
"It's a special game, I went from being a youngster to a man, I spent part of my youth here, I learnt a lot, not just on the field but off it," he added.
"I was here from 17 to 21, I had my first experience as a professional, playing games with great names and I also had some crazy times here.
"I left my family and friends and came to live on my own. I learnt a lot and returned a different person."
Pique was also briefly a team-mate of current United manager Ole Gunnar Solskjaer, playing alongside him for three seasons before the Norwegian's retirement in 2007.
"I remember Ole as a great team-mate - when I arrived here I was 17, I was very young, he was one of the older players," he said.
"He helped me a lot to adapt to the club, to the country and the city. It was a great experience playing alongside him, he helped me a lot and I'm very happy to see him in charge of the club."
