McGarrity was returning to the fold after an extended period out of the county colours and the Ballina Stephenites midfielder made an impression before being replaced at the interval by Donal Vaughan.
Mayo were never in trouble and their ability to raise green flags was noteworthy after a league campaign where they only hit the net on four occasions, and James Horan maintained afterwards that he was very happy with that aspect of his team’s display.
Westmeath were always playing catch-up, but had noteworthy displays from Ger Egan, Kieran Martin and Denis Corroon, who did their best in the face of almost constant Mayo pressure.
The home side had fine displays from Kevin Keane, Colm Boyle, Keith Higgins, Pat Harte and hat-trick hero Doherty, who showed magical predatory instincts to help himself to a handy return in the sunshine.
Scorers for Mayo: J Doherty 3-2, A Freeman 1-2 (2fs), M Conroy 1-1, C O’Connor 0-3fs, A Moran, R Mc Garrity 0-1 each.
Scorers for Westmeath: K Martin 0-4 (3fs), C McCormack, G Egan 0-2 each, A Giles, A Finnan 0-1 each.
MAYO: D Clarke; K Keane, S McHale, G Cafferkey; R Feeney, K Higgins, C Boyle; R Mc Garrity, B Moran; K McLoughlin, C O’Connor, P Harte; A Freeman, A Moran, J Doherty.
Subs: M Forde for McLoughlin (inj. 25), R Hennelly for Clarke, C Barrett for Feeney, L Keegan for Mc Garrity, D Vaughan for Moran, D Kirby for Conroy (all ht), E Varley for Harte (44), G Cafferkey for McHale (inj. 50).
WESTMEATH: G Connaughton; M Curley, J Gaffey, K Maguire; D Harte, M Ennis, B Moran; D Corroon, P Bannon; K Martin, G Egan, R Foley; A Giles, C McCormack, P McSharry.
Subs: M McCallon for Moran (24), D Gavin for Bannon (ht), R Foley for McCormack (ht), D McDermott for Curley (45), D Quinn for Connaughton (45), P Sheridan for Ennis (55), A Finnan for Martin (55), T English for McSharry (64), T Warburton for Egan (64).
Referee: Frank Flynn (Leitrim).