Conor Cox gave another ruthless display as Roscommon avoided any potential shock against Leitrim at Dr Hyde Park.
Instead, Anthony Cunningham’s men claimed their ninth championship win in a row over their neighbours.
They advance to a semi-final meeting with Mayo while Leitrim still haven’t beaten Roscommon in Connacht since 2000.
The home side were 3-6 to 0-7 ahead at half-time after goals from Shane Killoran (two) and Niall Kilroy.
Leitrim had Shane Quinn sent-off while Conor Daly was also shown red for Roscommon, with Diarmuid Murtagh getting black.
But Roscommon showed their class with their substitute inflicting further misery late on.
Leitrim midfielder Shane Moran was deployed on the edge of the square, and he had a goal chance after 30 seconds but goalkeeper Darren O’Malley got down well to smother the shot.
Leitrim would continue with their route one attack will up the other end Roscommon went straight for goal too. Their attack was more measured, but they wasted four goal chances in the opening quarter.
But Killoran did convert one after pass from the ever-industrious Kilroy in the sixth minute. Darren O’Malley popped over a 45 before Leitrim finally scored in the 12th minute, Ryan O’Rourke tapped over the free.
Domhnaill Flynn scored another free to reduce the arrears further, however, Killoran blasted his second goal after Ultan Harney’s hard work in the build-up in the 16th minute.
Roscommon would score an unanswered 1-3 with three points in a row from Diarmuid Murtagh but they didn’t pull clear.
Raymond Mulvey and Conor Cox traded scores before a couple of frees from O’Rourke and Flynn left just two goals between the sides in the 33rd minute.
Roscommon finished strong though, and Cox scored a point and gave the assist for Kilroy’s goal in the 35th minute.
Shane Quinn and Pearce Dolan answered that with two outstanding points from distance, but Leitrim trailed by eight points at the break.
Cox and Flynn (free) scored on the resumption and O’Rourke ate into the Roscommon lead with Emlyn Mulligan introduced to add some class and experience.
But Roscommon always had an extra gear and even though Diarmuid Murtagh was awarded a black card in the 53rd minute they were still too strong.
Cox continued to fire the frees and his huge effort from long range in the 55th minute was the highlight.
Quinn got his second yellow in the 61st minute and Conor Daly was sent-off in added-time but it didn’t make any difference to the result.
Roscommon: S Killoran 2-0, C Cox 0-5 (0-2f), N Kilroy 1-1, D Murtagh 0-3 (0-2f), A Glennon 0-2 (0-2f), C Compton 0-2 (0-1f), F Cregg 0-2 (0-1f), D O’Malley 0-1 (0-1 45), C Heneghan 0-1.
Leitrim: R O’Rourke 0-5 (0-5f), D Flynn 0-4 (0-4f), S Quinn 0-1, P Dolan 0-1, R Mulvey 0-1.
Roscommon: D O’Malley; C Daly, S Mullooly, D Murray; N Daly, C Hussey, R Daly (B Stack 64); S Killoran (C Fitzmaurice 70), T O’Rourke (F Cregg 37); H Darcy (C Devaney 48), C Cregg (C Compton 45), N Kilroy; D Murtagh (A Glennon 54, BC), C Cox (C Heneghan 61), U Harney.
Leitrim: C McCrann; M McWeeney, P Maguire, C Reynolds; D Flynn (N McWeeney 70), S McWeeney (O Madden 70), S Quinn; M Plunkett, F McTague (McGovern 22); R Mulvey, R O’Rourke, P Dolan (A Flynn 43); E Sweeney (J Heslin 39), S Moran, G Plunkett (E Mulligan 45).
Referee: Sean Hurson (Tyrone).