Alexis Sanchez says he considered skipping international duty with Chile this week after struggling to adapt to his new surroundings at Manchester United since his January switch.
The 29-year-old forward has scored one goal in 10 appearances since moving to Old Trafford in a swap deal which saw Armenian midfielder Henrikh Mkhitaryan join Arsenal.
"As I am self-demanding, I expected something better," Sanchez told the Chilean media while on national team duty in Sweden.
"After my arrival at United, it was hard to change everything very quickly. I even hesitated to come here (to Sweden)."
Sanchez completed his move to United on January 22 and made his debut in the FA Cup fourth-round win at Yeovil four days later.
He scored in United's 2-0 win over Huddersfield on February 3, his second Premier League appearance for the Red Devils after a loss to Tottenham, but has failed to net in seven appearances since.
He added: "The change of club was something that was very abrupt - it was the first time I've changed clubs in January - but many things have happened in my life that are difficult."
Chile missed out on qualification for this summer's World Cup in Russia.
Sanchez had sought permission to miss Saturday's friendly in Stockholm, but thought better of it after consulting Manchester City goalkeeper and Chile captain Claudio Bravo, who is not in the squad after reportedly turning down a call-up.
"I had asked permission to miss these games, but then I thought better and spoke with Claudio and told him that we should all be united," he added.