The Red Devils conquered England and Europe, but for the Welsh wizard it still wasn't enough.
For Giggs feel United will never have a better chance of repeating their glorious Treble success of 1999.
Their hopes of taking all three major trophies ended in a controversial 1-0 FA Cup quarter-final defeat by Portsmouth at Old Trafford.
Giggs told The Daily Mirror: "That grates with us because the Treble was possible last season. We should have beaten Portsmouth in the FA Cup quarter-finals.
"Strangely, that took the shine off the season for some of us. We knew we wouldn't have a better chance of doing the Treble again."
Now Giggs has one major aim this season, becoming champions of Europe once again.
He added: "I want to defend the Champions League trophy successfully this season. That's something nobody has done since it changed its format. That's the motivation for all of us."