The Scot clinched a 6-7 (6) 6-4 6-4 victory over 6ft 11in Opelka and will now bid for a 47th career title against Russia's Aslan Karatsev, who defeated Dan Evans in the other semi-final to dash hopes of a first all-British ATP Tour final.
It is a timely confidence boost for Murray ahead of next week’s Australian Open and will be his first chance at lifting silverware since winning the European Open in Antwerp in October 2019.
Here’s all you need to know about the final:
When is the Sydney Classic final?
The match between Andy Murray and Aslan Karatsev takes place on Saturday, January 15 at the Ken Rosewall Arena, Sydney, and is due to start at 8am UK time.
How to watch
The BBC has confirmed that Saturday's final will be shown live on BBC iPlayer, red button and BBC Sport website and app from 0800 GMT.
UK viewers can also watch via Amazon Prime Video. New subscribers can enjoy a 30 day free trial, including coverage of Murray’s final, before deciding whether to stick with the streaming service.
Prime Video costs £7.99 a month after the trial period and includes access to TV series from around the world, live sports events and next day delivery on selected Amazon orders.
Aslan Karatsev 4/6 Andy Murray 11/10 – Paddy Power