The holders and four-in-a-row All-Ireland champions led virtually throughout in front of 35,213 with Costello superb in attack and helping himself to 1-4.

The Whitehall Colmcille man memorably tipped the balance on Mayo with three points as a sub in the 2016 All-Ireland final replay and was excellent again.

It was his second Man of the Match performance at Croke Park this season having also impressed against Mayo's neighbours, Galway, in Round 2.

It was the perfect response from Dublin who went down by a point to Kerry in Tralee in Round 3.

Boss Jim Gavin took the opportunity to hand game time to Cian O'Sullivan, Ciaran Kilkenny, David Byrne and sub Darren Daly, bringing to 32 the number of players they've fielded in the league so far.

Kilkenny got on the score-sheet and was one of seven Dublin players to do so as they cantered to success.

Mayo came to Croke Park looking to reignite their old rivalry with the Dubs whom they lost All-Ireland finals to by just a point in 2013, 2016 and 2017.

But after an even enough first 20 minutes or so, the All-Ireland holders hit the afterburners to assert their authority once again.

It was 0-2 to 0-2 in the 19th minute when Costello scored Dublin's opening goal, leaving Keith Higgins for dead on the left before darting clear and beating Rob Hennelly at his near post.

Paul Mannion, Kilkenny, Costello and Jack McCaffrey all added points to put Dublin seven points ahead and they held a commanding 1-6 to 0-3 lead at the interval.

It could have been so much more with three Dublin point attempts dropping short and Mayo 'keeper Hennelly pulling off no less than four first-half saves, and six in total.

Mayo scored just one point from play in the first-half, an 18th minute score from talented newcomer Fionn McDonagh with Hennelly converting their other two scores from placed balls.

Mayo did have their chances but also dropped a number of point attempts short while Andy Moran blazed a shot wide and Jason Doherty had a 33rd minute penalty saved.

The second-half was a damp squib as Dublin went through the motions and outscored Mayo by 0-6 to 0-4 to stretch their lead to eight points by the final whistle.

It was all too easy for the hosts who held Mayo to just two points from open play after the break, from Matthew Ruane and sub Kevin McLoughlin.

The most intriguing moment was a bizarre collision between Mayo's Colm Boyle and an umpire which left the official requiring a lengthy period of treatment.

Scorers for Dublin: C Costello 1-4 (0-2f), P Mannion 0-2 (0-1f), D Rock 0-2 (0-1m, 0-1f), B Fenton 0-1, C O'Callaghan 0-1, C Kilkenny 0-1, J McCaffrey 0-1.

Scorers for Mayo: R Hennelly 0-2 (0-1f, 1 45), J Doherty 0-2 (0-2f), M Ruane 0-1, F McDonagh 0-1, K McLoughlin 0-1.

DUBLIN:

E Comerford; J Cooper, D Byrne, M Fitzsimons; J McCaffrey, C O'Sullivan, E Murchan; B Fenton, D Gavin; N Scully, C O'Callaghan, B Howard; P Mannion, C Kilkenny, C Costello.

Subs: D Rock for Kilkenny 49, P Andrews for Mannion 58, S Bugler for Howard 64, D Daly for Fitzsimons 65, MD Macauley for Gavin 67.

MAYO:

R Hennelly; K Higgins, G Cafferkey, B Harrison; L Keegan, C Boyle, P Durcan; M Ruane, D Vaughan; F McDonagh, A O'Shea, C Treacy; A Moran, B Reape, J Doherty.

Subs: C Barrett for Cafferkey 20, K McLoughlin for Treacy 35, S O'Shea for Durcan h/t, F Boland for Moran 58, S Coen for Reape 70.

Referee: B Cassidy (Derry).