Eddie Nketiah and Marquinhos were both on the scoresheet as Arsenal lost 4-2 to Watford in their first friendly of the World Cup break.
A team featuring Cedric Soares, Rob Holding, Gabriel Magalhaes, Martin Odegaard, Reiss Nelson and Albert Sambi Lokonga took to the pitch for the first half on Saturday at London Colney.
Midway through the half, Arsenal’s pressure told with a finish from outside the box by Brazilian youngster Marquinhos.
An equaliser from Keinan Davis was cancelled out moments later by Nketiah heading home a cross from Tierney.
Premier League leaders Arsenal led at the break before both sides made a raft of changes.
Davis, Yaser Asprilla and Joao Pedro all scored for Watford in the second period after the Gunners switched to a line-up of academy players.
Arsenal head to Dubai in the coming days for a warm-weather training camp ahead of the return of domestic action.
On December 8, they face Lyon in the Dubai Super Cup before a meeting with AC Milan five days later.
A friendly against Juventus at Emirates Stadium completes their preparations on December 17.
