Now they hope that 35-26 victory will inspire them to leap-frog Division Two West rivals Dunvant in the promotion places when they meet this Saturday.
And there are still hopes around the clubhouse at Newbridge Fields that they could soon have their first Wales jersey hanging in the bar with youth product Lee Byrne pushing for a call up to the national squad for this Autumn's International Series.
"Dunvant will be a big game for both sides but we have started the season pretty much exactly as we had hoped so hopefully we can keep that going," said coach Huw Hathaway.
"They haven't lost in the league yet but our victory over Newbridge in the cup has really given the boys a lot of confidence. People say the cup can be a distraction but at the moment it is giving the players a real buzz."
Full-back Stuart Morris was Athletic's cup hero with a stunning 30-point haul that included a try and seven penalties. He also converted a try from Tongan debutant Dylon Mafi.
"Stuart was lethal with the boot but we beat Newbridge because we wanted to play 15-man rugby against a very forward orientated side," said Hathaway.
"Newbridge wanted to bully us off the field but our pack fronted up, even though our oldest forward was only 23 years old, and our backs played some lovely rugby and were rewarded with a couple of length of the field tries. It was great to watch.
"Our team is full of local lads who have come through the system and that makes a big difference when it comes to gritting out a win, especially in the cup."
One of those to emerge from Athletic's youth ranks is Scarlets full-back Byrne who has been training with Mike Ruddock's Grand Slam winners after making a huge impression at regional level.
"The whole club is very proud of Lee who started with our Under-8s and went on to play two seasons of senior rugby," said Hathaway. "We're all hoping we might have our first Welsh jersey to hang in the clubhouse very soon."
In the meantime Athletic, third in the table thanks to prolific centre Robert Coles' tries and Simon Mustoe's leadership on the field, have their sights on battling back to Division One after coming straight back down after promotion two years ago.
Hathaway added: "We just pipped Dunvant for promotion in 2004 so I'm sure that will be on their minds. The cup run is great for the players and supporters but the real goal is to return to Division One."