Long battled past his Chinese compatriot Tian Houwei, eventually winning 21-14, 21-19 in an eagerly contested match that lasted all of 58 minutes.
In Sunday's final, the World Champion takes on Axelson, who surprised his Danish countryman Jan O Morgensen – the third seed – in their semi-final.
Axelson triumphed 21-17, 21-15 in a match 44 minutes in length against his more fancied compatriot.
Marin, the world number three from Spain, needed 43 minutes to beat Korean seventh seed Sung Ji Huyn, winning 21-13 21-14.
She will take on the fifth seeded Wang, who beat another Korean shuttler Baey Yeon Ju, the Chinese number two winning 21-19, 21-16 in 54 minutes.