Cillian O'Connor shot 1-09 as Mayo eased into a Connacht semi-final meeting next weekend against champions Roscommon with a 2-15 to 0-10 win in Carrick-on-Shannon.
James Horan’s men proved too strong for Leitrim in a game played in difficult conditions.
Mayo led by 1-06 to 0-06 at the break, having played against the strong breeze in the opening half, and they pushed on from there after the restart.
But Terry Hyland’s men made them battle for their win, laying out their stall when they raced into a 0-04 to 0-00 lead after ten minutes as they used the wind well.
Points from Shane Quinn, Evan Sweeney, Domhnaill Flynn and Keith Beirne gave them a solid foundation as they went in search if their first win over Mayo since 1994.
Aidan O’Shea had a big impact at full-forward and this gave Mayo a target man as they patiently built moves with Bryan Walsh getting them off the mark after eleven minutes before O’Connor landed two frees.
The first of those frees came after Leitrim’s Oisin MacCaffraigh received a black card and Mayo outscored the hosts by 1-04 to 0-01 during the ten minutes they had an extra man.
O’Connor landed two from play and Tommy Conroy crowned his championship debut with a superb goal after 23 minutes which he drove into the bottom left corner of the net.
Leitrim found scores hard to come by as Mayo tightened their defence.
Beirne got Leitrim’s first point in eight minutes after 18 minutes but they didn’t score again until just before the interval when Donal Casey finished a good move just before the break which also involved Donal Wrynn and Beirne.
Two frees from Beirne after the restart suggested Leitrim were going to press Mayo all the way but Horan’s men restored their goal lead thanks to another O’Connor free and one from Matthew Ruane.
Then O’Connor took a pass from Conor Loftus and blasted to the roof of the net to push Mayo 2-08 to 0-08 in front after 48 minutes and there was no way back for Leitrim after that.
Indeed, Mayo should have won by more but MacCaffraigh produced a brilliant block to deny Lee Keegan a goal.
And then Leitirm goalkeeper Brendan Flynn produced stunning saves to deny sub James Carr and Paddy Durcan as Mayo began to turn the screw.
It took a good save from defender MacCaffraigh to deny Lee Keegan and then goalkeeper Brendan Flynn produced point blank saves to deny James Carr and Paddy Durcan.
Mayo: David Clarke; Oisín Mullin, Stephen Coen, Lee Keegan; Paddy Durcan, Michael Plunkett, Eoghan McLaughlin; Matthew Ruane (0-01), Conor Loftus (0-01); Bryan Walsh (0-01), Ryan O’Donoghue, Jordan Flynn; Tommy Conroy (1-00), Aidan O’Shea (0-02, 1m), Cillian O’Connor (1-09 (0-04f, 0-02 '45s).
Subs: Diarmuid O’Connor for Walsh (48), James Carr (0-01) for O’Donoghue (48), Rory Brickenden for S Coen (51), Chris Barrett for Plunkett (62), Darren McHale for Ruane (64)
Leitrim: Brendan Flynn; Conor Reynolds, Oisin MacCaffraigh, Donal Casey (0-01); Cillian McGloin, Paddy Maguire, Aidan Flynn; Donal Wrynn, Domhnaill Flynn (0-01); Conor Dolan (0-01), Mark Plunkett, Jack Gilheaney; Shane Quinn (0-01), Evan Sweeney (0-01), Keith Beirne (0-05, 5f)
Subs: Riordan O’Rourke for A Flynn (55), Dean McGovern (for D Flynn (55), Pierce Dolan (Sean O’Heslin’s) for Sweeney (64), Tom Prior (for Dolan (68)
Referee: Paul Faloon (Down).