United will finish outside of the top three for the first time since the formation of the Premier League and will also not compete in the Champions League next year.
He told reporters: "Liverpool – where did they come last year, seventh? Who'd have said they'd be where they are this year? So a lot can change. We've certainly got the players and we've got everything in place to have a successful season next year.
"It's going to be hard, obviously, because we've had a tough season this year and the lads at Liverpool have improved and other teams around us have improved, so it won't be easy. But I'm confident we've got the players."
Giggs recorded a win in his first game as boss as United hammered Norwich City 4-0 at Old Trafford.