When Seo Seung Jae arrived at Copenhagen’s Royal Arena on 27 August 2023, he was on track to accomplish something no male player had achieved in nearly a quarter-century.

The last male player to win a double in a single edition of the BWF World Championships was Seo’s countryman Kim Dong Moon in 1999. Since then a couple of women players had achieved the double – Gao Ling 2001 and Zhao Yunlei in 2014 and 2015 – but for male players the task had seemed increasingly distant in an era of specialisation when few had the ability and the fitness to compete for gold in two disciplines.

The opening match was an intimidating prospect, with Seo and Chae Yu Jung running into Olympic silver medallists Zheng Si Wei/Huang Ha Yiong, who had beaten them in nine previous encounters.

“I had already lost to them nine times, so I knew very well how I lost,” Chae said. “If I didn’t pull ahead in the beginning, there would be no way to win against them. There was this unspoken understanding between us. At that time, I was really confident about my stamina, so I tried to move more and hit the shots more aggressively.”

Seo, though, saw the 0-9 record as an opportunity, for it meant they were going in as underdogs.

“Although we had lost quite a number of matches against them, since it was the final, we approached it with a more relaxed mindset and played with the mentality of challengers,” said Seo. “So, rather than feeling pressured in the final, I think we were doing what we could and played our own game.

“First of all, Zheng Si Wei and Huang Ya Qiong are extremely aggressive players with very few weaknesses, and they are incredibly fast. So, we knew we couldn’t afford to fall behind in terms of pace. In the past, we tended to play it safe during crucial moments, but this time we told ourselves that even if we were to lose, we wanted to play more boldly, without backing down and tried different strategies. That approach ended up working really well in this situation.”

After a game apiece, the Koreans started strong in the third game and led 16-9, but the gap started to narrow as the Chinese inched closer. The Koreans had five match points but Zheng and Huang knocked three of those aside.

“We’ve lost many matches where we were leading but got caught up and ended up losing,” Seo said. “In the final as well, we were up 20-15 and then gave away three consecutive points. At that moment, I told my partner, ‘Let’s not back down, let’s be bold. Even if we lose, don’t avoid the fight. Let’s keep pushing.’ I think that mindset helped us to stay calm and make the right plays, it all worked out well in that situation.”

Finally, on the 59^th minute, Seo Seung Jae and Chae Yu Jung were crowned mixed doubles champions – Korea’s first title in that discipline since Kim Dong Moon and Ra Kyung Min in 2003.

But Seo could not afford to relax – the men’s doubles beckoned.

“Right after we won the match point at 20 and secured the mixed doubles title, the moment I stepped off court, I immediately thought to myself, ‘Mixed doubles is done, now I need to focus on the men’s doubles.’”

Seo did have time to recover. While the next two matches (women’s doubles and women’s singles) were straight-game affairs going just over 40 minutes each, the men’s singles turned out to be a marathon featuring interminable rallies. The match took nearly two hours, and Seo was back on court some four and a half hours after he’d finished his first match.

“All I did was lie down. Recharge my energy as much as possible and make minimal movements so as to regain my physical strength,” the left-hander recalled.

Seo and partner Kang Min Hyuk were up against home pair Kim Astrup and Anders Skaarup Rasmussen, who had surprised everyone with their spectacular run.

Kang, aware that the mixed doubles would have taken a lot out of Seo, knew that he would have to leverage his physicality if the Koreans had to have any chance of winning.

“Firstly, I was younger, and I believed that I had a physical advantage over the Danish players,” said Kang. “Also, in terms of speed and movement, I thought I was faster than my opponents, so I tried to make good use of these attributes.”

Capitalising on home support, the Danes shot ahead in the opening game. The second was a neck-and-neck battle until 15.

“We lost the first game and in the second game, around 11 to 15 points, the match became very tight,” recalled Kang. “I usually focus more on net play, but I noticed that Seung Jae was getting a little tired. So, I moved to the backcourt, started to smash more and attack more aggressively. I think that was a key turning point in the match.”

Having turned the match around with six straight points, the Koreans kept a handy lead all through the third.

“First and foremost, with no mental distractions, my decision making became quicker,” said Seo. “When handling the shuttlecock, I kept my thoughts simple and just focused on what I needed to do at that moment. It allowed me to play more aggressively. Normally, I’d try to create opportunities or attempt complex shots, which often led to mistakes. But this time, I stopped overthinking and focused on simple actions like such as hitting and pressing forward. I trusted my partner at the back and confidently pushed forward at the net, this approach worked really well.”

The 14-21 21-15 21-17 result – achieved in 69 minutes – would be a milestone in Korean badminton. Seo Seung Jae had accomplished a rare double – the first by a male player in 24 years.

“Honestly, I don’t think I’ve ever felt this exhausted in any international tournament I’ve played,” said Seo. “Looking back, I don’t think I’ve ever reached the finals of two disciplines at such a major tournament before. Just making it to both finals already felt like a great achievement, but winning both of them in the end made me feel like I really did a great job.”

Seo will be defending his men’s doubles title at Paris 2025 with a new partner, Kim Won Ho. Given that the pair have been in outstanding form this season, few will discount Seo adding a third gold medal to his collection.