Ulsan took a 3-1 lead into the home leg of their tie with Bunyodkor Tashkent, and wrapped up victory with second-half goals from Kim Shin-wook and Lee Keun-ho for a 5-1 aggregate win.
A poor clearance from Hayrulla Karimov left Kim with a fairly straightforward task to net the opener after 53 minutes, and Lee then underlined the victory with an outstanding finish 16 minutes from time.
Later in the day, Al-Ahli reached their first ever Champions League final with a 2-0 win over Jeddah rivals Al-Ittihad.
Two-time winners Al-Ittihad had taken a 1-0 advantage from the opening leg, which was also played at the shared Prince Abdullah Al Faisal Stadium, but that was wiped out in the opening 45 minutes as their city rivals dominated.
Al-Ahli twice hit the woodwork before Moataz Al-Musa headed in a corner a minute before half-time.
Brazilian midfielder Victor Simoes then claimed the match-winner six minutes from time to send his side though to the November 10 final in Ulsan.
Wednesday's AFC Champions League Semi-final Second Leg Results
Ulsan Hyundai 2-0 Bunyodkor (5-1 on aggregate)
Al Ahli 2-0 Al Ittihad (2-1 on aggregate)