Clive Anderson has hosted the show since November
Michael Penrice, from Wigton, Cumbria was crowned the winner after battling through six rounds on cable TV station the Discovery Channel.
The 43-year-old clinched the title by just one point, choosing the history of England from 1603 to 1714 as his specialist subject.
Former host Magnus Magnusson sprung a surprise on the finalists by handing over the trophy to a delighted Mr Penrice.
The winner said: "I'm elated now but my initial feeling was one of relief, because the last few seconds were agonising.
"It feels amazing to have won, I've achieved a lifetime ambition."
Ninety-six contestants had taken part during the latest series.
The show originally ran on the BBC for 25 years until 1995, when the axe fell.
Mastermind was famed for its eerie theme tune and the spotlit black leather chair in which contestants sat while being asked a barrage of questions.
Digital
The BBC show was also memorable for its catchphrase "I've started so I'll finish", which was frequently used by Magnusson when the buzzer went at the end of a round.
Fast-talking chat show host Clive Anderson took over the reigns as quizmaster when the show was revived on Discovery last year.
The new version, which began in November, kept the old format but also lets digital viewers take part through their remote controls.
Four contestants take turns in answering questions on their specialist subject and general knowledge.
The final will be broadcast on the Discovery Channel on Wednesday 16 January at 2000 GMT.