Giggs was part of Manchester United's 1999 Treble winners.
And on City, he smiled: “I've got enough to worry about – please don't bring that up.
“They (City) are a fantastic team and they have obviously already got one. United going out of the FA Cup makes it a little bit easier for them.
“They have a long way to go, and just like us in the Treble, you need a bit of luck and a lot of things to go for you, which they had at the weekend.
“They're a brilliant team and it will be interesting to see what they can achieve."