The Basque region has a very proud tradition of rugby and share a very common ethos to Irish club rugby and such are the similarities, the game proved to be an enormous success both on and off the field.
Travelling with the majority of their league-winning side, Shannon were in a somewhat of a wind down mode but still managed to overcome their dogmatic opponents in a thrilling 42-40 victory.
A draw looked very much on the cards after the home side scored a late try, but the conversion attempt drifted wide and Shannon could celebrate yet another success.
The game started in sweltering heat and dehydration posed a potential problem for Shannon, but they managed to storm into an early lead through a Richie Mullane try.
However the home side soon rubbished any notions that this would be an easy run for Shannon.
The game turned out to be a real ding-dong affair which was punctuated with some brilliant flair and individual skills.
A super cross-field kick from Tadhg Bennett found the waiting David O'Donovan who gathered and scored his side's second try but it looked like Gernika would hold their 21-14 lead until the break.
Shannon rallied though, with Emmet McLoughlin crossing before five-time AIB League winner Frankie McNamara landed a spectacular drop goal from just inside his own half which certainly proved an inspiration for his colleagues.
Then it was the turn of Bennett who jinked and glided his way over the line to give Shannon a 24-21 half-time lead.
Gernika matched Shannon's physicality at times, but found it hard to cope with the pace and could do little to halt Shannon's gathering momentum in the second half.
The visitors stormed into the lead with additional tries from Fionn McLoughlin, Eoghan Grace and Paul Loughnane and now it looked as if Shannon would win easily.
Whether Shannon took their foot off the gas or it was the home side's pride and fear of defeat, but with 10 minutes remaining it was Gernika who were making all the running.
They stormed their way back into contention as the visibly-tired Shannon side began to wilt a little in the heat.
New to Shannon's senior ranks and playing their first senior games, replacements Sean Duggan and John Deegan made a difference when they were introduced and their energetic contribution ensured the rest of the Shannon outfit kept with the intensifying pressure.
In the end Gernika's late flurry added huge excitement to the game, but as the conversion drifted wide, the consensus amongst the 1,100 or so spectators was that Shannon were worthy of the win.
The Shannon travelling party was led by coach Geoff Moylan who was fulsome in his praise for the whole event.
"This was a fantastic way to reward the season's efforts by the lads and the IRFU are to be credited for their input," he said.
"The hospitality from the locals was brilliant and given the long season we've had, it's great to add another trophy to the cabinet.
"I'm very proud of the way the lads represented not only the club but Ireland and hopefully this competition will be continued in the coming years."
Shannon's 33-strong travelling party included club officials and newly-elected Shannon President Martin Clancy who was also fulsome in his praise for the event.
"We had a wonderful IRFU liaison in Sinead Bennett who was the epitome of professionalism and we thank her sincerely for the immense contribution she made to a very enjoyable weekend," Clancy said.
"The winning of the Basque cup was the icing on the cake and we would hope to return to the region as AIB League champions in the future."
SHANNON Squad: Frankie McNamara, David O'Donovan, Fionn Mc Loughlin, Jason Cronin, Padraic O'Brien, Fiach O'Loughlin, Marcus O'Driscoll, Sean Duggan, Joe Manuel, Emmet McLoughlin, Tadhg Bennett, Niall O'Brien, Danny Bedford, Paul Loughnane, Kevin Griffin, John Clogan, Frank Broderick, Eoghan Grace, Richie Mullane, Leonard Mullane, Killian O'Neill, Fergal Walsh, John Deegan, George Murray.