"Looking up at the scoreboard at the final whistle and seeing 2-0 was a horrible feeling, especially when you're up against a Championship side at Old Trafford," he told MUTV.
"I thought we started the game well and had some good possession. But their first goal brought them alive. After the break we didn't feel good and when they scored the second it was a horrible feeling.
"We know we did a lot of things wrong, but you can always learn from these situations and hopefully we will grow as players."
The third round tie represented a perfect opportunity for United's young guns to showcase their talents. Unfortunately it wasn't to be.
"Some people will think we've missed our chance," admitted Pique. "We're all very disappointed. We gave everything we could on the pitch, but things just didn't go our way."