Aidan Trihy swung over the winner in the fourth added minute for a 1-13 to 2-9 victory.
The victors trailed by four points on three occasions during the second half but scored 1-4 in the last quarter.
“When they were asked the questions, they answered them,” said winning manager Roger Ryan.
“Being four points down, it was a big task. We told them at half-time to keep going and that’s what they did. I’m very happy with the performance, but it’s early days. God only knows when we’ll be playing again!”
Clashmore have recruited former Cork boss Conor Counihan as coach for 2018. “He’s been there and done it at the very top level. It’s a great plus to have him involved.”
Tadhg De Burca returned from injury and slotted two first-half points. David Looby and Conor Prunty netted for Courty however as they posted 1-4 without reply either side of the break.
Substitute John Prendergast started the Clashmore comeback with a 49th-minute strike. Paul O’Connor punched them into the lead.
Mark Ferncombe equalised before Trihy produced the winner.
Champions Stradbally shook off a second half fightback from a plucky Portlaw to emerge 1-17 to 1-10 victors.
Paul Tobin’s goal fired them 1-10 to 0-4 clear at halfway.
A Peter Boylan goal followed by three Michael Donnelly points cut the gap to four with ten minutes left.
Eoin O’Brien and Tommy Connors closed it out for the winners.
Shane O’Meara shot 2-4 as The Nire beat Brickey Rangers 4-15 to 4-9. Three goals in ten first-half minutes from Michael O’Gorman, Shane Walsh and O’Meara put them in charge.
John Kirwan netted twice in Rathgormack’s 3-11 to 2-9 win over 14-man Kilrossanty. Joey Veale and Kirwan traded goals in the first half as the sides were level at the break (1-4 each).
The victors cut loose once Kirwan had their second goal. Stephen Curry added a third. Veale lashed in a drop kick consolation from a close range free. James Whyte was dismissed on two yellows.
An Rinn and Gaultier couldn’t be separated (0-11 apiece). Gaultier registered the last three points (two from JJ Hutchinson and one from Billy O’Keeffe) to nab a draw. Gavin Crotty and Luke O’Callaghan goaled as Dungarvan attained their first win against Ardmore (2-18 to 2-10).