A barnstorming second half display propelled outsiders Roscommon to the Connacht Under-20 Football Championship title at a sun-drenched MacHale Park in Castlebar on Wednesday evening.

The winners played some scintillating football, dominated in all sectors, and were full value for their comfortable 2-11 to 1-07 victory.

Goals from Adam McDermott and man of the match James Fitzpatrick did most of the damage as Mayo failed to justify their pre-match favourite's tag.

Roscommon, who are managed by Liam Tully, had beaten Sligo convincingly in last week’s semi-final and were gunning for the county’s first title at this grade for six years.

Apart from the first quarter, they dominated a disappointing Mayo, outscoring the home side by 2-11 to 1-04 after the first water break.

Maurice Sheridan’s side were unable to rediscover the form they showed when beating All-Ireland champions Galway in last week’s provincial semi-final, and their woes were compounded when Jack Mahon had his penalty saved in the closing stages.

Ronan Garvin of Roscommon in action against Connell Dempsey of Mayo

Despite starting slowly, the eventual winners led at half-time by 0-05 to 0-04.

Mayo had come flying out of the blocks and were three points up by the first water break thanks to scores from Jack Carney, Jack Mahon (free) and Conall Dempsey (free).

The Rossies finally opened their account on 17 minutes through James Fitzpatrick and they were level nine minutes later after Darragh Heneghan and Ben O'Carroll hit the target.

The momentum was now with the visitors and they edged ahead when Fitzpatrick and Cregg both pointed in quick succession. But Mayo had the final say in the half when midfielder Jack Carney landed his second score of the evening in additional time.

Roscommon's Ben O'Carroll and Ruairí Keane of Mayo jostle for a dropping ball

The writing was on the wall though for a misfiring Mayo and Roscommon struck a major blow on 40 minutes when Adam McDermott fired past goalkeeper Ronan Connolly from close-range.

That green flag left Mayo seven points down but they were thrown a lifeline on 46 minutes when referee Thomas Murphy awarded them a penalty and sent Roscommon captain and full-back Colin Walsh to the sin-bin.

However, Jack Mahon's kick was well saved by goalkeeper Conor Carroll.

The last quarter saw Roscommon kick on to close the game out and the outstanding James Fitzpatrick crashed in a second goal on 54 minutes to seal the deal.

Mayo: R Connolly; S Holmes (0-01), R Keane, D McHugh; C Flynn, R Baynes, A Cosgrove; C Dunleavy, J Carney (0-02); E Henry, C Reid, C Dempsey (1-02, 1f); U O’Reilly, F Irwin, J Mahon (0-01, 1f).

Subs used: P Heneghan for O’Reilly; D Thornton for Reid; E Duffy for McHugh; O McHale (0-01) for Cosgrove; R Morrin for Mahon.

Roscommon: C Carroll; C Lohan, C Walsh, D Gaughan; P Gavin, T Crean, C Glennon; K Doyle, R Garvin; R Dolan, J Fitzpatrick (1-03), D Cregg (0-05, 3fs), B O’Carroll, A McDermott (1-00), D Heneghan (0-01).

Subs used: R Fallon for Garvin; J Doorey for Heneghan; J Lohan for Glennon; D Wynne for Crean; S Trundle for McDermott.

Referee: T Murphy (Galway)