Tom Cleverley has admitted the dreadful performance may have been influenced by him starting too many who had been away on international duty.
The head coach will be forced to watch the game from the stands as he serves a one-match touchline ban.
Francisco Sierralta will only meet up with the rest of the Watford squad in a hotel later today after flying home from Chile.
The former Watford Women head coach follows Tom Cleverley and Paul Robinson into the black chair.
Fearne Cotton, Jack Whitehall and Sheridan Smith also attended the 2024 launch of the Hogwarts in the Snow feature at Warner Bros. Studio Tour.
The Hornets have a proud history in the prestigious competition, lifting the trophy in 1982 and 1989
Vakoun Bayo and Mamadou Doumbia scored their first senior goals as both their nations qualified for the finals in December 2025.
The dismissal of James Clarridge after 10 minutes was a significant factor in the 4-1 defeat despite the Hornets going 1-0 up.
Giorgi Chakvetadze deservedly took the man of the match award but there were others who also excelled against Oxford.
Michael Adu-Poku grabbed a goal and an assist as Solihull Moors overcame a red card to score six times in the second half at Ebbsfleet United.
