Nash was thrust into the action in the 110th minute of a knockout semi-final clash against Tuggeranong United and became the man of the moment in the penalty shootout after scores were locked at 2-2 after extra time.

The Cooma junior admitted he was full of nerves, but the adrenaline helped him stop two Tuggeranong shots to seal a remarkable victory, setting up preliminary final showdown with Canberra FC next weekend.

League champions Canberra FC fell to Canberra Olympic 5-3 at Deakin Stadium on Saturday night as the rivals went head to head in an attacking masterclass.

Olympic moves straight into the Canberra premier league grand finals after scoring three first-half goals and Roko Strika slotted their fourth with six minutes left.

Canberra FC hit back in the 89th minute when Daniel Subasic gave his team last-minute hope of sending the game into extra time.

But Strika won a penalty two minutes into injury time and converted from the spot to send his team into its fifth grand final in the past six seasons.

The eight-goal bonanza was the perfect way to end a day of high drama, during which Nash got on the field for the first time this year when regular Tigers goalkeeper Jakob Cole was sent off in extra time after getting his second yellow card.

"Amazing. I didn't get up after [the winning save] for a bit because I didn't realise. It feels pretty amazing when it clicks and you get the result," Nash said.

"I've been playing [in the under-20s] and been helping out Jakob where I could. He's an amazing keeper, the best option we have. It was a shame about [being sent off], but that's football. You've got to adapt.

"I probably put in some extra hours next week, but we'll be ready and we'll come out firing. I've still got nerves now, the adrenaline is still surging. But it's good."

Nash's brilliance at the end was a fitting way to finish an absorbing contest, but a heartbreaking way for Tuggeranong to be knocked out of their first finals campaign in 15 years.

"We just didn't have the luck we needed. This is a good group of guys, I thought we were going to win in 90 minutes, but it wasn't to be," said shattered Tuggeranong coach Mitch Stevens.

"I'm just replaying the chances we had in my head over and over. When [Nash] comes on like that, adrenaline through his veins and a point to prove, you just don't know."

The rampaging Tigers, who have lost just one of their past 10 games. The only game they lost was a match against Canberra Olympic when the club rested the bulk of the squad gave under-20s players a chance to shine.

The Tigers will ride their wave of confidence into the next round and they started with a bang against Tuggeranong when Nicolas Villafane hammered home two long-range attempts in the first 20 minutes.

The Argentinian has now scored 18 goals and his efforts in the opening exchanges had Tuggeranong on the back foot in their first finals game since 2003.

But Tuggeranong has built a steely resolve this season under Stevens' guidance and got back in the contest when Shane Murray stepped up to curl one passed Cole into the bottom-left corner.

It was Tuggeranong's first goal in a Capital Football finals series since 1994, and they had to wait until the first minute of injury time to score the equaliser when Regan Walsh tapped a cross into the net.

Tuggeranong hit the post twice in the second half and squandered two chances in extra time, but they couldn't land the killer blow. Cole's red card tipped the contest in Tuggeranong's favour. At least that's what everyone thought.

Nash took charge and saved Daniel Roberts' opening penalty shot, before Jakeb Wiseman had the answer for Tuggeranong when he stopped Tony Spaseski's attempt.

Tuggeranong's Tom Pagett put his shot over the top and then Nash became the hero when he saved a shot from Matt King to end the match.

"It was a final, anybody can win. Tuggeranong did OK and played very well," said Tigers coach Gaby Wilk.

"I'm very happy. We haven't lost any games [in the second half of the season] ... Cody had no worries. He's worked very hard all season, always sitting for us and to have the chance in the final, unbelievable."

AT A GLANCE

Grand-final qualifier: CANBERRA OLYMPIC 4 (Michael John 14', Dom Giampaolo 18', Stephen Domenici 44', Roko Strika 84', 90') bt CANBERRA FC 3 (Matthew Waters 45', Michael Mensah 55', Daniel Subasic 89') at Deakin Stadium.

Elimination final: TIGERS FC 2 (3) (Nicolas Villafane 9', 17') bt TUGGERANONG UNITED 2 (2) (Shane Murray 22', Regan Walsh 91') on penalties at Deakin Stadium.