Alonso joined Real Madrid in a £30million deal earlier this week.
The Dutchman said: “Xabi is a very good player but these kind of things happen in football.
“Teams are changing all the time. Xabi played very well for Liverpool but that’s all history now and we have to move on.
“We have to look forward. That is what Xabi is doing with Real Madrid and we have to do the same.
“We have signed a new player with a lot of quality, that is how we must view things.
“We have a lot of good players still here and are all determined to go one better in the league after coming so close to winning the title last season.”
