Insert ACF data in Wordpress custom post type through REST API (front-end)

My goal is to be able to insert data using JavaScript fetch method.

Inserting the post worked like a charm, but I can only insert the post title and status. How can I insert ACF data?

fetch('http://mywebsite.com.br/wp-json/wp/v2/athletes/',{
    method: "POST",
    headers:{
        'Content-Type': 'application/json',
        'accept': 'application/json',
        'Authorization': `Bearer ${this.state.userToken}`
    },
    body:JSON.stringify({
        title: 'my custom post title',
        status: 'publish',
        acf: {
          my_field: 'my acf value here'
        }
    })
}).then( (response) => {
    return response.json();
}).then( (post) => {
    console.log(post);
});