West Brom missed two penalties as Roberto Di Matteo started his rein as manager with a 1-0 defeat at Histon.
Debutant Simon Cox and Luke Moore both saw their spot kicks saved by Danny Naisbitt on a frustrating afternoon for the Baggies.
Jamie Barker earned Histon the win with a 64th-minute strike moments after he had hit a post.
Source: Eurosport