The Sharks have bounced back from their Magic Round humiliation by holding off a fast-finishing Sea Eagles to win 20-14 at Brookvale Oval on Sunday.
Cronulla were in cruise control for the opening 60 minutes but Manly - who lost Josh Aloiai to a dislocated shoulder - scored two late tries to set up a grandstand finish.
Their third straight loss was amplified with worrying signs for fullback Tom Trbojevic who Cooper Cronk declared nowhere near 100 per cent on the eve of Origin selection.