Murray has had his finest run of results since winning his 46th career championship in Antwerp in October of this year.
The three-time Grand Slam winner has had a fantastic week and is in good shape ahead of the Australian Open next week.
Murray has been on the verge of a deep run in a tournament, including victories against top ten players in 2021.
He was disappointed to lose the first set against 6ft 11in Opelka after rallying from 1-5 in the tie-break, but he maintained pressuring on his opponent's serve and was rewarded with a 6-7 (6), 6-4, 6-4 triumph.
Murray has always fared well against large servers, thanks to his excellent returns and ability to keep the ball in play.
He is 7-0 versus Ivo Karlovic and 8-0 against John Isner, and this victory keeps him unblemished against the game's titans. “It’s already been a great week for me. I’ll go for 47 tomorrow.” said Murry.
Murray will now compete for his 47th career championship against either compatriot Dan Evans or Russia's Aslan Karatsev in what would be the first all-British ATP Tour final.
Murray was given a wildcard for the Australian Open, which takes place next week in Melbourne and in which he has reached the final four times.
He's lost all four times against Novak Djokovic, but the Serb's participation in this year's Grand Slam appears uncertain after his visa was once again denied.
Murray will play Nikoloz Basilashvili, the 21st seed, who he defeated in the final of the Sydney Tennis Classic.