Murray booked his place in the last four after recording a walkover quarter-final win over David Goffin - who retired injured after the first set - and took on 6ft 11in American Reilly Opelka on Thursday.
Opelka took the first set 7-6 (8-6) following a tense tie-break, during which Murray let a 5-1 lead slip through his grasp, but the three-time Grand Slam winner responded with 6-4 6-4 wins in the second and third sets to march onto the final.
Murray has now reached an ATP Tour final for the first time since beating Stan Wawrinka in the showpiece event at the 2019 European Open, but Evans's eye-catching run in the tournament came to an end in the last four.
The British number two took on top seed Karatsev and slumped to a 6-3 first-set defeat, but a lengthy tie-break in the second set kept the tie alive as Evans rallied to post a 7-6 (15-13) second-set win.
However, after Evans's foul-mouthed tirade towards officials over Karatsev's five-minute bathroom break, the Brit went down 3-6 in the deciding set to bow out at the penultimate hurdle.
Karatsev and Murray will battle for glory in Sydney on Saturday, while Evans now prepares for his Australian Open first-round tie with Goffin next week.