Alexis Sanchez says he has fulfilled a dream by joining Manchester United but hit out at suggestions that he ever gave less than his best while playing for Arsenal.
Sanchez swapped clubs with Henrikh Mkhitaryan on Monday after both players secured their work permits, having already undergone medicals at the weekend.
The Chilean didn't leave quietly though with a message to his detractors on his social media pages.
He wrote: "There are people (former club players) who have spoken with no knowledge of what happens inside the club and cause damage.
"I must say I always gave 100 percent, until the last day, when I asked to the Mister (Arsenal manager Arsene Wenger) to be in the team because I wanted to be a contribution."
He added: "I remember today, a conversation I had with Henry, a historic Arsenal player, who changed club for the same reason and today is my turn."
Sanchez also thanked the Arsenal fans for their support over the years before revealing it was a dream come true for him to join United when it appeared as if he was destined for Manchester City.
"Thanks for everything Gunners! All we achieved and the good moments that I gave to the club, I want to dedicate it to the fans, they are the most important. Thanks for every time you sing Alexis Sanchez Baby."
Speaking to MUTV, Sanchez added: "Since I was a young lad I've always said that my dream was to play for Manchester United, and I'm not just saying that because I'm here now and today it's come true.
"I always said as a kid that I'd like to play for United and I once spoke to Sir Alex Ferguson about it. We chatted for around 20 minutes. And I told him that my dream was to come here to Manchester United.
"It really is a massive club, very powerful, and so now, when I got the opportunity to come here, I looked at the badge and my hairs just stood up on end because it's a powerful club and the biggest in England."