Yoshimura, the ninth seed, recovered from 3-2 down to claim a 11-9, 8-11, 13-11, 13-15, 6-11, 11-8, 11-9 victory at the Queen Elizabeth Stadium.

Zhang earned singles and team titles at the London 2012 Olympics and followed that with team gold and singles silver at Rio 2016.

He also secured singles gold medals at the 2011 and 2013 World Championships and is considered among the greatest players in the history of the sport.

But, despite remaining among the most recognisable athletes in China, the 30-year-old has struggled in recent years and barely competed internationally since a shock second-round exit to South Korea's eventual bronze medallist Lee Sang-su at last year's World Championships in Düsseldorf.

"Zhang is a player I respect a lot and I knew that it's his first tournament after a long rest," the victorious Japanese player said. 

"I am happy to have had the chance to play against him. 

"It is a precious experience for me to learn."

Egypt's Omar Nassar awaits for Yoshimura in the second round after he beat Singapore's Gao Ning 11-7, 11-9, 11-9, 9-11, 12-10.

Elsewhere in the men's singles draw, top seed Wong Chun Ting of Hong Kong dispatched Daniel Habesohn of Austria 11-7, 13-11, 14-12, 12-10.

Wong will take on Sweden's Jon Persson, who overcame France's Emmanuel Lebesson 11-8, 11-3, 11-4, 11-9.

In the women's singles, top seed Kasumi Ishikawa suffered a shock defeat at the hands of South Korea's Lee Eun-hye.

Lee proved too strong for her Japanese opponent and clinched a 11-6, 11-5, 11-9, 11-6 victory to progress to the second round.

Chen Ke of China will play Lee tomorrow after she ousted Miyu Kato of Japan 11-2, 11-6, 10-12, 11-9, 9-11, 11-8.

The tournament continues tomorrow.