Manchester City were turned over by Olympique Marseille in their NextGen clash in France last night.
Despite a fine second-half performance after leaking an early goal at the Stade Marcel Cerdan, the young Blues were caught out twice more in their second defeat of their opening games.
Now victory over Celtic at Ewen Fields on 17 October is essential if City are to remain in contention for a top-two finish and a place in the knockout stages this winter.
Blues coach Welsh gave a NextGen debut to 15-year-old Angus Gunn, the son of Norwich City legend Bryan Gunn, in goal.