Fifth seed Chen Long of China tumbled out of the world badminton championships on day one on Monday, beaten by little-known Kevin Cordon of Guatemala.
Cordon, the world No. 36, clinched victory on his fourth match point 21-19, 8-21, 27-25 in a 74-minute thriller.
“It’s the biggest win in my life by far,” Cordon told reporters. “Since March I have been training in Spain with the national team, so that has been good. I can play more tournaments in Europe.”
“To play against one of the top players in the first round is not a good draw, but that is what you are training for. So I just said I will play my best game,” he said.
His second-round opponent is Finland’s Henri Hurskainen, who beat England’s Carl Baxter 21-8, 21-19.
Chen, 22, failed to convert three match points.
“I never thought I would lose, but I am still young,” he said.
It also wasn’t a good day for Taiwan’s Hsueh Hsuan-yi, who lost to South Korea’s Park Sung-hwan 21-15, 21-15.
Top seed Lee Chong Wei started his bid for a maiden world title with a 21-15, 21-17 win over Thailand’s Tanongsak Saensomboonsuk.
The Malaysian world No. 1 was made to work hard by the gritty Thai, who took five points in a row in the second game to lead 11-8.
However, Lee, aided by some deceptive returns of serve, regained control to move safely into the second round.
Former world and Olympic champion Taufik Hidayat, the other big name on parade at the Wembley Arena on the first morning, was held at 6-6 in the opening game by Peru’s Rodrigo Pachecho Carrillo.
However, the Indonesian soon pressed on to lead 15-7, before clinching a 21-10, 21-14 victory.
World titleholder Chen Jin breezed past Estonia’s Raul Must 21-8, 21-10.
On day one in the women’s singles, Olga Konon of Germany beat Taiwan’s Ying Tai-tzu in a walkover.