In the only game of the men’s and women’s competitions to survive the weather, South African import Hosking — in Dublin for a couple of months during his native land’s off-season — did all the damage against the 2009 champions.
Rovers had the better of a scoreless first-half, though neither side offered much at corner time, largely thanks to the absence of any noted drag-flickers and the excellence of goalkeepers Andrew Whitaker of C of I and Rovers’ Wendel Armstrong.
Rovers did have one corner effort from Ross Varian chalked off for failing to find the backboard, but there was nothing wrong with Hosking’s classy opener.
The diminutive, pacy midfielder saw off three tacklers en route to the circle, before rounding Whitaker and finishing with a reverse-stick finish.
And he doubled the Dubliners’ lead soon after, doing superbly to get enough elevation on a diving reverse to lift the ball over the logged Whitaker, who had saved Luke McSharry’s initial short corner strike.
C of I setup a tense last quarter when Mark Holmes cracked a rocket of past the despairing dive of Armstrong, but Rovers ultimately won out in relative comfort.
Meanwhile, UCC were left to rue a golden opportunity to shock an off-colour Cork Harlequins, who progressed to the Peard Cup final with a 2-1 win.
College went behind early on to a David Eakins drag-flick, but subsequently came out on the right side of the possession and short corner statistics.
From one of the latter, Andy Gray faked a drag-flick and switched left to younger brother Roger, who rifled home an equaliser.
But College went behind again as Paul Lombard produced a second Quins goal, and they had the chance to make it more comfortable on the final whistle, but Eakins saw his penalty stroke saved by Kieran Healy.
Quins will now meet either Bandon or Cork C of I on St Stephen’s Day.
Elsewhere, second-half goals from Ciara O’Herlihy, Caroline McCarthy and Emma Harrington helped Ashton pick up a comfortable 3-0 win at Belvedere to move into fourth place.
Jane Bourke grabbed two goals on her return to Catholic Institute and Roising Upton netted a hat-trick, as the Limerick girls hammered a youthful Cork C of I side 8-0 to extend their lead at the top of the Munster league to seven points, albeit with two extra games played.
Meanwhile, there was no happy return to former club Hermes for Chloe Watkins and Niamh Atcheler, whose UCD side were routed 4-0 in the only top-level game to go ahead in Leinster.
Lisa Jacob, Aine Connery, Anna O’Flanagan and Laura Pinder did the damage for the hosts, who have moved a point clear of Loreto with a game extra played, but will be sweating on the fitness of Irish international drag-flicker Audrey O’Flynn after she sustained an ankle injury.