The world number 5 Indian shuttler, who won the title back-to-back in 2009 and 2010 before losing the crown last year, had little difficulty in disposing off her unseeded Korean rival 22-20 21-18 in the women's singles semi-final, which lasted exactly 50 minutes.
Saina will face fourth seeded Xuerui Li of China in the summit clash tomorrow. Li stunned top seed and compatriot Yihan Wang in the other semi-final.
The road to the third Indonesia Open title won't be easy for Saina as she holds a dismal 1:4 head-to-head record against Li.
The day, however, witnessed mixed results for India as earlier another Olympic-bound Indian shuttler P Kashyap failed to cross the semifinal hurdle of the Super Series Premier event, losing 15-21 12-21 to world number nine Simon Santoso in a 46-minute men's singles match at the Istora Gelora Bung Karno Stadium.
Contrary to the final result, Saina looked a little sluggish against Sung initially, especially after her energy-sapping quarterfinal contest against world no. 4, Shixian Wang of China yesterday, which lasted one hour and 37 minutes.
But as the match progressed, Saina picked up her game and played well enough to secure a place in the final.
To Saina's liking, Sung was erratic and committed numerous unforced errors that worked in the Indian's favour.
Even though Saina looked sluggish in the opening game, she enjoyed a comfortable lead over her opponent till the first 17 points before Sung made a spirited comeback with four straight points to level the scoreline at 17-all.
From there on it was a tight battle between the two players but eventually Saina, who won the Thailand Open Grand Prix Gold last week, did enough to hold her nerve and pocket the first game.
The second game witnessed a keen contest between the two players with none of them willing to give an inch to the other.
It was an even affair between Saina and Sung till the first 16 points in the second game before the Indian surged ahead to 20-17 with some fine net play and then finally pocketing the game and the match.
However, the day did not start on a good note for India as world number 26 Kashyap struggled against Simon in the men's singles semi-final.
Kashyap matched Simon initially but the Indonesian broke the Indian's game plan and moved into the break at 11-10. Simon varied the pace of the rallies and pushed Kashyap into committing mistakes to lead 14-13.
Simon had a better idea of the court and made some sound line judgments. With Kashyap faltering at the nets and his strokes going wide, it allowed Simon to enjoy a five-point cushion at 20-15. Another mistake with a cross court net shot and Simon was leading the match 1-0.