Joe Salisbury says becoming the first Briton to reach the ATP Finals doubles final is "extra special".
Salisbury and American Rajeev Ram, the reigning US Open champions, fought back to beat top seeds Nikola Mektic and Mate Pavic 4-6 7-6 (7-3) 10-4 in their Turin semi-final.
Second seeds Salisbury and Ram lost in the last four of the 2020 event.
In the singles, defending champion Daniil Medvedev beat Norway's Casper Ruud in their semi-final.
The Russian second seed won 6-4 6-2 and will face Serbia's world number one Novak Djokovic or German third seed Alexander Zverev in Sunday's final.
Salisbury and Ram will play France's Pierre-Hugues Herbert and Nicolas Mahut or Spanish-Argentine pair Marcel Granollers and Horacio Zeballos in the doubles showpiece.
On becoming the first British doubles player to reach the final, 29-year-old Salisbury said: "It is a big achievement and I'm really proud of it.
"Hopefully there will be many more after me.
"But we don't want to just get to the final - we want to be the ones winning it."
Another impressive season for Salisbury and 37-year-old Ram has enabled them to add the US Open title to their 2020 Australian Open success.
Now, after beating Wimbledon and Olympic champions Mektic and Pavic, they have the chance to finish their season together with another prestigious title.
After losing the first set, Salisbury and Ram fought back to level and then raced into a 6-1 lead in the match tie-break.
In last year's semi-final, they let a 7-1 advantage slip against Jurgen Melzer and Edouard Roger-Vasselin, but ensured there would be no repeat as they clinically closed out victory.
"The way we did it, coming from being a set down and not playing our best, we were up against it and showed a lot of fight and character," added Salisbury.
"We believed we could turn it around and play our best at the end."