Led by 13 points and eight rebounds from Mairi Buchan plus 12 points and six boards from Mary Durojaye, the GB side led for most of the game after a strong second period put them in the driving seat.
GB didn't shoot the ball well inside the arc, managing only 28 percent of their two-point efforts, but hit half of their three point attempts and out-rebounded the Slovaks 48-35.
Kristie Sheils added nine points and five boards, with Rebecca Allison finishing with nine rebounds and three assists for a GB team that gave at least seven minutes of action to all 12 of their roster.
Slovakia were led by 16 points from Klaudia Lukacovicová and 14 from Veronika Cernáková, and will be consoled by the fact that they will join GB in Division A next season.
GB started well with a Durojaye lay-up giving them an 8-4 lead midway through the first period. Cernáková made it a one-point game with a trey, but Charlotte Stoddart extended the GB lead before a Kashmere Joseph free-throw sent them into the first break 11-7 ahead.
Sheils gave the Slovaks a taste of what was to come by hitting a trey to put Britain 14-7 up at the start of the second period before repeating the act to make it a ten point game. Buchan made it 22-9 just after the five minute mark, and a late Renee Busch score sent the GB side into the locker room 25-14 ahead.
That lead grew to 12 as Alison converted an and-one with 7:27 on the clock in the third period, but Slovakia chipped away to make it 34-29 at the midway stage of the stanza. Another Sheils score from downtown kept GB's nose in front, and Buchan's driving lay-up with two minutes of the penultimate period remaining was the last score before GB went into the final break 41-36 ahead.
Felixova cut that lead to three 62 seconds into the period and the same player made it a one-point game before Novocka put Slovakia up for the first time, 44-43 with 5:02 on the clock.
After a scoreless spell, Buchan put GB back up by one going into the final three minutes of the game, and Durojaye kept them ahead at the 1:52 mark after Lukacovicova had restored the Slovak's lead.
The lead was still 47-46 when Slovakia called a timeout with 35 seconds on the clock, and when they resumed Novochka missed a three point effort 17 seconds from time.
However Kristie Sheils turned the ball over when she stepped out of bounds with 10 seconds on the clock to force a GB timeout. Cernakova drove to the basket but missed the lay-up, and Durojaye grabbed the rebound to seal the title for GB.
