Livvy Dunne rocked a fitting accessory to watch her boyfriend, Paul Skenes, finish off his one-of-a-kind rookie season ... a pair of one-of-a-kind boots!

The feet heat -- which Dunne sported to cheer on the Pirates ace in his 2024-25 finale against the Yankees on Saturday -- featured a white Skenes Pittsburgh jersey on a pair of white Cowboy boots ... and TMZ Sports has learned Jessica Martini made them by hand.

The artist tells us she just recently came up with the idea for the footwear after leaving her tech consulting job ... and after she was able to make some pairs for the wives of MLB All-Stars Aaron Nola and Will Smith earlier this season, she reached out to Dunne to see if the LSU gymnast would want some of her own to cheer on her man.

Martini says as soon as she got the yes ... she went to work -- and drove some six hours to Pittsburgh to scoop the Skenes supplies.

Once secured and back in her garage, Martini then tediously cut and placed the uniform on the kicks -- and after a total of 20 hours ... the masterpieces were ready for Dunne.

Livvy paired them with some jean shorts and a black top for Skenes' dominant two-inning outing against the Yankees ... and she clearly loved them -- posting pics of her in them all over her social media page. She even took a snap in them with Skenes himself!

Martini says she was thrilled with the outcome ... and tells us not to be surprised if you see some similar boots later this week -- as she says she's already got a pair ready for Clayton Kershaw's wife for the Dodgers' upcoming postseason run.

So far, the boots aren't ready for public sale -- Martini says the business is just getting off the ground -- but she's hoping to link up with a retail giant sooner rather than later so the masses can get their hands on them at some point in the near future.