World number 2 Saina defeated Indonesia's Lindaweni Fanetri (world number 29) in straight games 21-17, 21-17 in the semi-finals at the Istora Senayan stadium on Saturday.
In the final tomorrow (August 16), she will face world number 1 Carolina Marin of Spain. 25-year-old Saina took 55 minutes to wrap up her semi-final match.
This is the first time Saina has entered the World Championships final. She is also the first Indian ever to feature in a World Championships title round.
Saina, who won bronze at 2012 London Olympics, holds a 3-1 advantage over Carolina in head-to-head record. The most recent meeting happened in March this year when Saina was beaten by Carolina 21-16, 14-21, 7-21 at the All England Open final.
In the first semi-final, Spaniard Carolina edged South Korea's Sung Ji Hyun 21-17, 15-21, 21-16 in a three-game battle that lasted 1 hour and 30 minutes.
Going into the semi-final match, Saina was the heavy favourite but her opponent got a very good start. Saina took some time to attain momentum as Fanetri held a 6-2 lead.
But once the former World No.1 found her rhythm, she seized the initiative and pushed her rival on the backfoot. Fanetri was forced to play catch up but remained close to Saina's score.
The Hyderabadi held a 3-point lead at 14-11 but Fanetri kept coming back, equalising at 15-all. They were involved in a long rallies for the next two points.
However, at 17-17, Saina utilised her experience and finished the game in her favour by taking three consecutive points. Saina's deft net play played a key role in getting the better of the local talent of her same age.
At the start of the second game, when the score read 2-1 in favour of the strong favourite Saina, Fanetri suffered a knock to her heavily bandaged right knee after a fall but continued her fight.
Urged on by a vociferous partisan crowd, Fanetri kept fighting on even though she seemed to be struggling in her movement on the court.
At the break, the 2nd seeded Indian held a 11-10 lead at the break before Fanetri equalised. Saina grabbed three points at a stretch to make it 14-11 but Fanetri drew level at the same score with sharp drop shots.
But Saina fought back for a 17-14 lead before her opponent employed two sharp smashes to make it 16-17. Saina got two more points before her opponent reduced the deficit to one at 18-17.
However, Saina once again wrestled the key moments as she bagged three consecutive points to seal the game 21-17 and march into the final.
India's previous medals at World Championships - 4
1983 - Prakash Padukone (Men's Singles) - Bronze
2011 - Jwala Gutta and Ashwini Ponnappa (Women's Doubles) - Bronze
2013 and 2014 - PV Sindhu (Women's Singles) - Bronze