The towering centre-back is cheering for his former team ahead of the Champions League tie, and has hailed Barca's strength in depth
The Spain international wore the United jersey from 2004 until 2008, and he is hopeful that his former team can beat Barca's arch-rivals in the round of 16, with the first leg of the tie scheduled to take place at the Santiago Bernabeu on Wednesday.
"I would like Manchester United to make it to the next round," Pique told reporters.
"I would like them to progress because of my time at the club. However, Madrid have been in good form in recent weeks. It promises to be an interesting tie."
The centre-back then went on to discuss Barcelona's 6-1 Liga win over Getafe on Sunday afternoon, and hailed his side's strength in depth.
"We have a very complete team. A few players who don’t usually enjoy a lot of minutes [on the pitch] got to play on Sunday and they proved that they are at a good level. This gives us tranquility."
Barca went 12 points clear of second-placed Atletico Madrid following the Rojiblancos' loss against Rayo.