Cavan are safely through to the second round of the qualifiers after an impressive demolition of London at Ruislip on Saturday - but the win came at a cost as two defenders went off injured.
First to go was Killian Clarke, who suffered a recurrence of the hamstring strain which kept him out of the loss to Monaghan last month.
More seriously, Rory Dunne was stretchered off in some distress in the second half. The full-back landed awkwardly and was removed via ambulance after an 11-minute delay.
While the extent of Dunne's injury is not clear, there are fears the Redhills man has suffered a dislocated ankle.
Cavan raced into a 0-11 to 0-4 half-time lead, with Niall McDermott kicking five first-half points.
London rallied but following Dunne's injury, Cavan kicked into a higher gear, with the outstanding Gearoid McKiernan landing 1-3 in five minutes and Dara McVeety punching a second goal en route to a 17-point win.
Cavan had a stranglehold at midfield, where Tomas Corr and McKiernan impressed.
Cavan: R Galligan 0-1 (45); J McLoughlin, R Dunne, K Clarke; C Brady, F Flanagan, D O'Reilly; T Corr 0-3, G McKiernan 1-6; D McVeety 1-2, N Murray 0-1, M Reilly 0-1 (f); R Flanagan, M Argue, N McDermott 0-5 (2fs). Subs: C Mackey 0-1 for Clarke (11 mins), J McEnroe for Dunne (53 mins), E Reilly 0-1 for Flanagan (60 mins), M McKeever 0-1 for Brady (66 mins), P Smith for M Reilly (66 mins), K Brady for Murray (70 mins).
London: D Traynor; B Collins, P Butler, S Curran; M McCoy, C Carty, D McGreevy 0-1; M Carroll, A Bradley; S Conroy, M Gottsche, C Og Greene; A O'Hara 0-3 (1f), L Mulvey 0-6 (4fs), A Moyles. Subs: N Boyle for Carty (16 mins, bc), L Gavigan 0-1 for Moyles (33 mins), A Carr for O'Hara (46 mins), C Sheridan for Conroy (60 mins), A O'Regan for Bradley (65 mins), S Devine for McCoy (66 mins).
Referee: P Neilan (Roscommon).