I know that American football isn't everyone's cup of tea over there, but let me give you an analogy.
In 2007, the University of Alabama hired Nick Saban as its head coach, despite the fact that he had just flopped very hard in the NFL with the Miami Dolphins. In his first season, Saban was not very successful, going 7-6 and losing to Louisiana Monroe (essentially the equivalent of Wycombe beating Arsenal). Many fans wanted Saban gone after that loss, which was also a home game (and Homecoming [basically an annual event in which tons of alumni come back to the school to reminisce and also watch an easy victory for the football team], to boot).
Saban was not fired, and Alabama has lost only 11 games in 9 years since. They have won 4 national titles since and Saban now has an overall 85% win rate.
On the day of the Louisiana Monroe loss, Saban said that sometimes great things are built from great tragedy.
This loss can be the moment from which great things are built with this team. That is, IF (and it is a big if) Zenga and the players have the mettle for it.
Time will tell.