The big Dane, who had lost nine of his previous 10 clashes to the Malaysian, saw off the veteran in a one hour, 12 minute epic, coming from behind to win 14-21, 21-14, 21-19.
It meant Axelsen was the second qualifier from Group B and he now faces either Tian Houwei or Jan Jorgensen on Saturday for a place in the season-ending final at the Hamdan Sports Complex.
Axelsen held his nerve in the deciding set, with Lei conceding the match with a fault on serve - a gift the 22-year-old described as an “early Christmas present”.
Incidentally, it was the second time in a row the 6'4 powerhouse had got the better of four-time end-of-season champion Wei in Dubai.
“I'm very, very happy. He's a player I looked up to as a little child and the first time I played against him in 2012, I was like: 'Woah, how do I get to that level'.
With top contender Pusarla V Sindhu also falling to Sun Yu, the group was thrown open. The final group matches on Friday will decide the semi-finalists.
Japan’s Yamaguchi sustained her fast paced style even in the later stages of the match to outlast Marin 18-21 21-17 21-14 in 86 minutes, the longest match of the tournament so far.
Earlier, Sun Yu got her second big win on successive days, beating crowd favourite Sindhu 21-15 21-17.
In contrast to Group B, the semi-finalists from Group A were decided on Thursday, with Tai Tzu Ying joining Sung Ji Hyun in the knockout stage. World No.1 Tai was untroubled by the less-than-fully-fit Ratchanok Intanon (Thailand) as she eased to a 21-12 21-14 result.
Malaysia’s Goh V Shem and Tan Wee Kiong won a thrilling 58-minute battle against Li Junhui and Liu Yuchen to cement their semi-final place from Group B of Men’s Doubles.
Li/Liu’s second loss meant that they have no hope of progressing to the knockout stage.
Goh and Tan kept their nerve in a tight finish, edging past the Chinese duo 18-21 21-19 21-19. The Malaysians’ next match with China’s Chai Biao/Hong Wei will decide the group winners.
And in Men’s Singles, Korea’s Son Wan Ho recovered from a big deficit to upstage last year’s runner-up Viktor Axelsen, 21-19 14-21 21-18 in 76 minutes.
Axelsen had a 10-4 lead in the decider, but seemed to lose patience during the rallies as he attempted quick winners. The Dane’s mid-game lapse saw him allow Son to go ahead 14-12, and despite stemming the flow, Axelsen couldn’t regain the momentum at the end.
Malaysia’s Lee Chong Wei kept alive his hopes of making the knock-out stage with a 21-15 22-20 victory over Hong Kong’s Ng Ka Long. Still showing signs of rust after his injury layoff, Lee managed to finish the game in straight games despite trailing for most of the second.
“Perhaps today’s performance was better than yesterday’s,” said Lee. “I wasn’t 100 percent. Perhaps that’s because I haven’t been playing any tournament for the past two months and I haven’t had the feeling of playing competitive badminton. Today is only the second match and I hope for a better performance tomorrow.”
Earlier in the day Mads Conrad-Petersen and Mads Pieler Kolding played some of their best badminton to defeat three-time World Superseries winners Kevin Sanjaya Sukamuljo/Marcus Fernaldi Gideon (Indonesia) in their Men’s Doubles Group A encounter, while Japan’s Takeshi Kamura/Keigo Sonoda recovered from Wednesday’s loss to record a 33-minute victory over Indonesia’s Angga Pratama/Ricky Karanda Suwardi, 21-15 21-9.
China’s Chen Qingchen and Jia Yifan overcame mid-match resistance from second seeds Christinna Pedersen/Kamilla Rytter Juhl to grab their second straight win in Women’s Doubles Group B and Korea’s Jung Kyung Eun/Shin Seung Chan won a tight battle over Malaysia’s Vivian Hoo/Woon Khe Wei, 21-19 21-17.
In Group A, Korea’s Chang Ye Na/Lee So Hee got their second straight win with a 21-14 21-10 result over Japan’s Kurumi Yonao/Naoko Fukuman.
Jan O Jorgensen and Tian Houwei guaranteed themselves of semi-final places in Men’s Singles with comfortable victories in Group A. Denmark’s Jorgensen needed just 37 minutes to beat familiar rival Marc Zwiebler (Germany), 21-18 21-10, while Tian overcame Hong Kong’s Hu Yun 21-19 13-21 21-7 in just over an hour.
Action in the BWF Dubai World Superseries Finals continues with the finals being played on Sunday 18 December. The order of play, results and all the details can be found at http://www.dubaisuperseriesfinals.ae.
Carolina Marin is one of the biggest names in world badminton.
At 23, the Spaniard is already a double world champion and Olympic gold medalist.
For aspiring athletes wanting to get into the sport, in this video Marin shares her top tip.