Sir Alex Ferguson made six changes from the side that beat Arsenal on Saturday and the Red Devils fell behind early in the second half after Alan scored from the spot.
However, substitute Robin van Persie netted from outside the area with 10 minutes remaining, before Wayne Rooney’s penalty and Javier Hernández’s strike in stoppage time sealed victory.
“I think we were all disappointed [we didn’t progress from the group stage last year],” said Giggs.
“It was not good enough and we knew we had to do something about it and we have. Long may it continue.
“We have really good strength in depth at the moment and it shows with Chris Smalling playing his first game in a long time tonight.
“It is good to have that strength when you have two games in a week and it is looking good for us.”
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