The 32-year-old stood on the brink of retirement after testing positive for an anti-inflammatory steroid at the 2014 world championships last October, with the prospect of a two-year ban set to bring a premature end to a glittering career.
Lee appealed on the grounds that the substance he had taken inadvertently had no performance-enhancing qualities. The successful outcome was backdated and the suspension reduced to eight months, meaning he was back on court chasing his dreams in May.
A low-key return gained momentum with back-to-back titles in North America and he arrived in Jakarta having lost just one match, to world number one Chen Long. His improving form carried him into the semi-finals.
Badminton
Inclusion of new Paralympic sports hailed as 'game-changing' by GB Taekwondo CEO Archibald
03/09/2021 AT 15:00
Unseeded due to a loss of ranking points during his layoff, Lee has ousted three seeds on his march to the last four with Friday's 21-12 21-18 victory over Hong Kong's Hu Yun his most impressive performance in the Indonesian capital.
"I played my best match today. It is a good sign as I will be up against a tough opponent in the semi-finals. I will treat it like a final," Lee told reporters.
"Hu Yun was a different player today...he was more aggressive but I was prepared for him. I controlled the front of my court and also focused on every point," added the player who has spent a total of 298 weeks at the top of the rankings.
Next up for Lee is a tough encounter against improving Dane Jan O Jorgensen, the second seed, who denied supporters the chance to witness a dream semi-final between the Malaysian and his arch nemesis Lin Dan with a comfortable 21-12 21-15 victory.

Jan O Jorgensen of Denmark hits a return against Lin Dan of China during their quarter-final men's singles match of the 2015 World Championships badminton tournament in Jakarta on August 14, 2015

Image credit: AFP

Chinese five-times world champion Lin has beaten Lee in four major finals and has dominated their rivalry but the 31-year-old was philosophical in defeat and will hope to target a third straight Olympic title in Rio next year.
"I didn't play well today, was well below my peak and unable to perform to my best," Lin said. "But winning or losing is common in this sport and I will not be burdened by worrying over the result of this match."
Tokyo 2020
'Joy overwhelming' - Wild, emotional celebrations as Indonesian underdogs make badminton history
02/08/2021 AT 11:05
Tokyo 2020
'What a sensational victory!' - Indonesia pair celebrate wildly after badminton gold
02/08/2021 AT 09:49