The World Championship bronze medalist toppled defending champion Lee Zii Jia of Malaysia to enter his maiden final at the BWF World Tour Super 1000 tournament.
The in-form Sen squeezed past World No. 7 Lee Zii Jia 21-13, 12-21, 21-19 in a grueling men's singles semi-final match. The marathon last-four clash lasted an hour and 16 minutes, including a thrilling final game spanning 32 minutes.
It marked the second straight win for Sen over his Malaysian rival. The World No. 11 had beaten Lee Zii Jia six years ago at the Sats India International Series.
Lakshya Sen becomes youngest Indian to reach All England final
The 20-year-old Lakshya Sen became only the third men's singles player, after Prakash Padukone and Pullela Gopichand, to reach the final. Padukone (1980) and Gopichand (2001) are the only Indians to have won the prestigious event, while Saina Nehwal reached the final in 2015.
At 20, Sen has become the youngest to reach the final of the oldest tournament in the world. The Uttarakhand shuttler has been in splendid form in the last six months. He secured his maiden Super 500 title at the Indian Open in January before grabbing a runner-up finish at the German Open last week.
The unseeded Sen will take on the winner of top seed Viktor Axelsen (Denmark) and fourth seed Chou Tien Chen (Chinese Taipei) in the summit clash on Sunday.
Lakshya Sen off to brilliant start against sixth seed
Both Lakshya Sen and Lee Zii were cautious initially, checked out each other's lengths of stroke and netplay. Sen, playing from the faster side of the court, got a lot of smashes back with ease but pushed a few out at the baseline.
Nevertheless, he managed to regain control of proceedings, leading 11-7 at the interval. Lee Zii, who stunned second seed Kento Momota in the quarter-finals on Friday, appeared slower than he was against the mighty Japanese. That allowed Sen to maintain his lead as he claimed the first game 21-13 in 21 minutes.
Lee had a good start in the second game, though, leading from start to finish. The defending champion wrapped up the second 21-12 to make it 1-1. Both players went neck-and-neck in the decider. At 9-9, Lee reeled off two points to lead 11-9 at the mandatory change of ends.
Lee stepped up the pace and led 16-12, but Sen staged a spectacular comeback, reducing the deficit to a single point. With both players hitting their stride, there was hardly any margin for error.
Lee took a two-point lead at 18-16. However, Sen kept his cool to move ahead 19-18. He had two match points at 20-18, but Lee saved one. However, Sen converted his second to book his place in the final.
Gayatri Gopichand and Treesa Jolly go down fighting in women's doubles semis
Treesa Jolly and Gayatri Gopichand Pullela went down fighting against Zhang Shu Xian and Zheng Yu in the women’s doubles semis.
The Chinese pair, ranked 276th in the world, halted the spectacular run of Jolly and Gopichand with a 21-17, 21-17 victory in a well-contested clash lasting 50 minutes.
World No. 46 Jolly and Gopichand fought hard in both games but could not deliver the knock-out punch. The teenage Indian women’s doubles pair reached the semi-finals in their maiden appearance at the All England Championship but went no further.
The 19-year-old Gopichand is the daughter of former All England men's singles champion Pullela Gopichand. Meanwhile, Jolly hails from Kerala and is a year younger than Gayatri Gopichand.
Lakshya Sen bt 6-Lee Zii Jia (Malaysia) 21-13, 12-21, 21-19 (76 minutes).
Treesa Jolly-Gayatri Gopichand lost to Zhang Shu Xian-Zheng Yu (China) 17-21, 16-21 (51 minutes).