in the saddle
US /ɪn ðə ˈsæd.əl/
UK /ɪn ðə ˈsæd.əl/

1.
in sella, al comando
in a position of control or responsibility
:
•
After the CEO retired, his successor was quickly in the saddle.
Dopo il ritiro del CEO, il suo successore fu rapidamente in sella.
•
With the new manager in the saddle, we expect significant changes.
Con il nuovo manager in sella, ci aspettiamo cambiamenti significativi.