All-Ireland title hopefuls Mayo waited until their seventh Championship game to show their very best form, burning off Roscommon with ease to secure an All-Ireland semi-final clash with Kerry.

Stephen Rochford's side wrapped up the replay win long before half-time despite losing Footballer of the Year Lee Keegan, who scored 1-03 in the drawn game, from their line-up.

Keegan was among the substitutes at Croke Park but missed out due to an apparent leg infection that required hospital treatment.

Mayo didn't miss him in the all-Connacht affair and three goals between the 23rd and 29th minutes - opening up a 13-point lead at that stage - put the result beyond doubt.

Mayo led 0-06 to 0-02 when Kevin McLoughlin got the goal siege underway, cutting through the centre of Roscommon's defence before firing in right footed.

Andy Moran blasted a low shot to the net 40 seconds later following a probing run by defender Keith Higgins who scored Mayo's third after an even better solo run up the field.

It was all too easy for Mayo who were held to a 1-12 to 2-09 draw by the Connacht champions when the sides met on July 30.

It was easily Mayo's best performance of an epic Championship campaign that has required extra-time against Derry and Cork in the qualifiers as well as this replay date.

All of Mayo's big guns fired in front of a 39,154 crowd with Cillian O'Connor scoring Mayo's fourth goal in the 46th minute and finishing with 1-06.

Moran helped himself to 1-01 while Aidan O'Shea was terrific in attack and scored two points, earning the Man of the Match award.

Roscommon, managed by former Mayo All Star Kevin McStay, picked up seven bookings on the day including two for Fintan Cregg who was red carded in the 53rd minute.

The game was long since beyond doubt at that stage with Mayo manager Rochford running in his full allocation of substitutes.

The standard will rise sharply for Mayo when they meet the Munster champions on 20 August in the last four of the Championship.

Donal Vaughan and Tom Parsons were late additions to the team in place of Keegan and Ger Cafferkey and Mayo hit the ground running.

The scored six points through Cillian and Diarmuid O'Connor, Vaughan and Jason Doherty before Roscommon managed their opening score.

Then came the three goals which displayed Mayo's ruthless streak and left Roscommon's hopes of progressing in tatters.

O'Shea and Doherty closed out the first-half scoring to leave Mayo 3-08 to 0-04 ahead.

O'Shea stretched the gap after the restart before O'Connor's goal which came from a short Roscommon kick-out that was turned over and punished.

Mayo carved out at least half a dozen goal chances overall and continued to savage Roscommon with points from Moran, Cillian O'Connor and Chris Barrett.

Substitutes David Drake, Shane Nally and Stephen Coen contributed four points between them as Mayo powered on towards the finish line with little let up, and now it's Kerry standing in their way of another big day in September in their quest for that long-awaited Sam Maguire. 

Mayo: D Clarke; B Harrison, D Vaughan (0-01), K Higgins (1-00); C Boyle, C Barrett (0-01), P Durcan; T Parsons (0-01), S O'Shea; K McLoughlin (1-00), A O'Shea (0-02), D O'Connor (0-01); J Doherty (0-02), C O'Connor (1-06, 0-06f), A Moran (1-01).

Subs: C Loftus for Doherty 46, D Drake (0-01) for McLoughlin 55, A Dillon for Moran 61, S Coen (0-01) for Vaughan 61, D Kirby for A O'Shea 62, S Nally (0-02) for Barrett 66.

Roscommon: C Lavin; S McDermott, N McInerney, D Murray; J McManus, S Mullooly (0-01), B Stack; T O'Rourke, E Smith (0-01); C Fitzmaurice, N Kilroy (0-01), C Devaney (0-01); Cathal Compton, D Murtagh (0-04, 0-02f), C Connolly.

Subs; C Murtagh for Compton h/t, G Patterson for McDermott h/t, F Cregg for Connolly h/t, D Smith (0-01) for B Stack 47, I Kilbride for Devaney 60, Colin Compton for E Smith 63.

Referee: A Nolan (Wicklow).