Odion Ighalo returned to the starting 11 for Watford but couldn’t prevent them from losing 2-0 away to Southampton.
Shane Long put Southampton ahead in the 16th minute.
In the second half, Dusan Tadic doubled Southampton’s lead when he struck in the 74th minute.
The loss now leaves Watford 10th in the Premier League table.
They have now lost in consecutive games.