Japan enjoyed one of their best days in badminton history on Friday as the men sensationally knocked out powerhouse China 3-0 in the Thomas Cup and the women entered the Uber Cup final.
The men will take on Malaysia - 3-0 victory over Indonesia in the second semi-final- in their maiden Cup final on Sunday at the Siri Fort complex in the Indian capital.
The women fought back gallantly from 0-2 to defeat hosts India 3-2 and qualify for Saturday's final against China, who prevented further embarrassment by routing South Korea 3-0.
China, the overwhelming favourites seeking a record sixth consecutive Thomas Cup title, never recovered after Chen Long lost to Kenichi Tago in the opening singles.
World number two Chen lasted just 43 minutes against the aggressive fourth-ranked Tago to go down 21-13, 21-11.
Japan made it 2-0 through the doubles pair of Kenichi Hayakawa and Hiroyuki Endo, who beat Chai Biao and Hong Wei 22-20, 21-19.
It was left to 19-year-old Kento Momota to seal the tie for the 2012 semi-finalists by coming from behind to upset world number six Du Pengyu 23-25, 21-18, 21-14 after an hour and 25 minutes.
World champion Lin Dan, who was due to play the fifth match, was left stranded as the Japanese celebrated a famous win even as the Chinese stormed out of the stadium in a huff without speaking to the media.
"This is an unexpected result for sure," said Japan's Korean coach Park Joo-Bong, a former world and Olympic doubles champion.
"But what surprised us even more was Momota's win in the third match that gave us the tie. A loss there could have made it a bit tough for us.
"If China had won the next doubles, there was Lin Dan waiting in the last game. And very few people beat him these days.
"We will go into the final with a lot of confidence. Hopefully we can go on to win the Thomas Cup for the first time."
Malaysia made it to their first final since 2002 by cruising past 13-time champions Indonesia in a disappointing one-sided semi-final.
After world number one Lee Chong Wei had outclassed fifth-ranked Tommy Sugiarto in straight games, Tan Boon Heong and Hoon Thien How upset world doubles champions Mohammad Ahsan and Hendra Setiawan 21-19, 8-21, 23-21.
With the cushion of a 2-0 lead, Chong Wei Feng ensured Malaysia's entry into the final by beating Dionysius Rumbaka 21-10, 21-17 in the third match.
The Indian women, cheered by some 2,000 boisterous home fans, took a 2-0 lead through their two top singles players, Saina Nehwal and P.V. Sindhu.
But the Japanese drew level after Misaki Matsutomo and Ayaka Takahashi won the doubles and Eriko Hirose beat P. Thulasi in the third singles.
India fielded the scratch combination of Nehwal and Sindhu for the decider, but the move backfired as Miyuki Maeda and Reika Kakiiwa raced to a 21-14, 21-11 win.
The Chinese women, whose 12 Uber Cup titles include seven in the last eight editions, toyed with South Korea, the team they beat in the 2012 final.
World number one Li Xuerui dominated the fifth-ranked Sung Ji-Hyun 21-11, 21-19 in the opening singles, before Bao Yixin and Tang Jinhua won the doubles against Jang Ye-Na and Kim So-Young 21-11, 21-12.
World number two Wang Shixian completed the easy win by beating Bae Yeon-Ju 21-13, 16-21, 21-10 in the third match.