The Sentinel was called to intercept a Rebel attack at the heart of the Imperial surveillance satellite network near Coruscant itself. However, it arrived too late to prevent the lone Rebel X-wing from destroying the satellites and the transports that were mining the area.
The Sentinel later guarded a supply depot in Hollan D1 sector. However the supply depot got attacked by X-wings and Y-wings and the Mon Calamari Star Cruiser Cathleen in which it entered hyperspace with the Cathleen in pursuit.