The former Fiorentina midfielder moved to the Hammers on deadline day.
“I always dreamed of playing in the Premier League," said the Colombia midfielder, who completed his move to West Ham from Italian club Fiorentina on deadline day.
“It was previously in Aston Villa, where we started very well, then things did not go so well, but I always kept the idea of returning and here I have the same ambition, the same desire, the same dreams and I'm very grateful to West Ham for the opportunity."
Sanchez hopes to see action against Liverpool on Sunday.
“We all want to play games against the big clubs, to be able to measure yourself and see how you are, but personally I prefer to meet all the big boys at the beginning and not when they have fine-tuned their style more. It may be an advantage or not, but I prefer it that way."