Alonso, 31, has gone on to win the Premier League, Champions League and FA Cup with the Blues.
"I have come a long way since then," Alonso told the club's website.
"After a lot of challenges, you grow as a person and a player. It's the experience that can help you the most.
"All the good things, all the bad things, it's what makes you improve and what makes you better. I think I'm a much more mature person now with a big career behind me, and hopefully more to come.