Pablo Fornals scored twice as West Ham finished the Europa Conference League group stage with a perfect record by beating FCSB in Romania.
With top spot in Group B and a place in the last 16 already assured, manager David Moyes opted to give some of West Ham's promising youngsters a chance to shine, and they made the most of the opportunity by contributing to a dominant display.
But it was the experienced Fornals who made the telling difference, his double helping to secure a sixth win from six group games.
Fornals scored his first before the break with a fierce drive before a header by 18-year-old debutant Divin Mubama was turned over his line by Joyskim Dawa.