Mac Mail 13.4. How to enter new email address, without autocomplete?

When entering a new email with a common prefix, for example helpdesk@, Mail will autocomplete this address to a previously found domain. Typing the entire address containing a new domain does not get out of this autocomplete, and will replace the new domain with the autocompleted domain, even if finished with a comma. Space or tab replaces the typed email with the autocompleted email. Delete removes the address completely. "Remove email" does the same.

How can you force enter a new email address, without Mail interfering and changing it to something it already knows?