The opening weekend of the Connacht championship served up a second shock in less than 24 hours as Roscommon upset the odds to knock Mayo out of the provincial title race at Hastings Insurance MacHale Park.First half goals from the Smith brothers — Enda (from a penalty) and Donie — set Roscommon on their way to a deserved victory as league champions Mayo crashed to only their second defeat of the season.The Rossies, who led from start to finish in a match that never really caught fire in front of a crowd of 19,361, will now face Galway in the provincial semi-final on Sunday week next.This was just their second time to beat their neighbours in championship football at this venue since 1986, coming four years after their last successful visit.Kevin McStay's Mayo, meanwhile, will now have a six-week break before they are back in action in the group stages of the All-Ireland series.The Smiths' goals helped Roscommon to lead by four points at half-time, but Mayo came roaring back in the third quarter and scores from Mattie Ruane, Tommy Conroy and Aidan O’Shea left just the bare minimum between the teams after 50 minutes.But the Rossie’s defensive system, allied to the pace of their counter-attacks, continued to pose problems for a Mayo side that seemed to feel the effects of last week’s National League Final in the last quarter.The winners outscored the homeside by 0-05 to 0-02 in the last 20 minutes with Enda Smith leading the charge, time and time again. As it Happened: Mayo 0-10 Roscommon 2-08 A couple of inspirational points from Diarmuid Murtagh, along with a free from the St Faithleach’s attacker, were followed by a fine score from Conor Cox to leave Roscommon up by 2-07 to 0-09 after 67 minutes.Down at the other