Goals from substitutes Bastien Hery and Christy Manzinga gave Linfield a 2-0 Champions League preliminary semi-final win over 10-man Tre Fiori.
Hery found the top corner with a long-range effort after 71 minutes before debutant Manzinga wrapped up the win seven minutes from time.
Tre Fiori defender Giacomo Pracucci was sent off in the closing stages for a rash challenge on Kirk Millar.
The game was played behind closed doors at a neutral venue in Switzerland.
Northern Ireland's Linfield will face either Drita or Inter Club d'Escaldes in Tuesday's final, with the winner of that match progressing to the Champions League first qualifying round.
In a game of few clear-cut chances, Linfield enjoyed the majority of possession with Millar almost netting the opening goal early in the second half after being found by Niall Quinn's cross.
But the Blues - who also handed debuts to Chris Johns and Navid Nasseri - were made to wait for the breakthrough as Hery's rasping drive handed David Healy's side the edge over their Sammarinese opponents.
Then, with seven minutes remaining, a mistake from Tre Fiori goalkeeper Aldo Simoncini allowed summer signing Manzinga to tap home the second and send Linfield into the final.
"I'm absolutely delighted to go through," Healy told the Linfield website.
"It was a tough game, we knew they would make it difficult for us. We had a couple of opportunities in the first half that we didn't quite capitalise on.
"The subs came on and made a difference and got us two big goals.
"He [Manzinga]'s very direct, Christy went out onto the left hand side. It gave us more options. From 60 minutes on, we had Andy Waterworth, who replaced Shayne [Lavery], we had Millar, [Daniel] Kearns, Manzinga and we had Hery pushing forward, so we had a right go at it.
"I always felt as though we were the better team but you're always wary of a mistake or a set-play. I thought overall our fitness levels were good, our concentration levels were high and the best team won on the day that's for sure."
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