Add class dynamically from functions.php to div on singe product page – woocommerce

On a single product page (Woocommerce) a plugin in adding the following div structure:

<div class="variations-table">
<div class="variation">tennis</div>
</div>

I would like to add <?php $variations> (already defined) to the “variation” class so I can style these classes depending on the name of the variation.
So the result for a variation called “tennis” should be:

<div class="variations-table">
<div class="variation tennis">tennis</div>
</div>

How can I achieve this dynamically via my functions.php file, so I do not have to touch the plugin files?