Sanchez shared a screenshot on Instagram of an account which posted a string of monkey emojis on his page.
He accompanied the Instagram story with the caption “Nothing changes” and a sleepy emoji, expressing the depressing regularity with which players are being targeted online.
The incident followed Tottenham’s 2-2 draw at Newcastle on Sunday, in which Sanchez played 90 minutes and lost possession in the build-up to the hosts’ opening goal by Joelinton.
The Colombian centre-half joins a long list of high-profile players who have been racially abused on social media of late, with the game increasingly frustrated over big tech’s lack of action over the issue.
Manchester United trio Anthony Martial, Axel Tuanzebe and Marcus Rashford, Borussia Dortmund’s Jude Bellingham and Chelsea’s Reece James are among the other players to have been targeted and called out the abuse.
During the international break, Wales players Ben Cabango and Rabbi Matondo, both 20, were racially abused on Instagram via direct message, leading to an investigation by South Wales police.
Facebook, owners of Instagram, last month responded to calls to step up efforts to combat racist abuse by announcing new penalties, but questions were immediately raised as to whether the measures go far enough.