The 29-year-old Spaniard slapped her singlet in delight as she crossed the line in one hour, 25 minutes and 54 seconds, a comfortable 12 seconds ahead of Mexico’s Alegna Gonzalez in second place.
It was a redeeming moment for Perez, who had missed out on an Olympic medal by eight seconds at the same National Stadium in 2021.
“I am the happiest woman in the world,” Perez said. “I did not come here today to make history in women’s sport. I just came to improve myself and not to focus on the time.
“Last time in Japan, I left with a bitter-sweet taste. I am leaving happy now,” said Perez, who also did the walk double in Budapest two years ago.
To the delight of the roaring crowd, Nanako Fujii just held off charging Ecuadorian Paula Milena Torres at the line to finish third and secure Japan a first global medal in the women’s walk events.
It was Japan’s second medal at the 20th World Athletics Championships after Hayato Katsuki’s bronze in the men’s 35km walk.
In weather conditions considerably kinder than the punishing heat of the 35km walk a week ago, the top medal contenders clung together in the leading pack for more than half of the race.
With a few kilometres remaining, Perez eased away to take control of the race with her fluid, confident strides.
Olympic champion and world record holder Yang Jiayu of China finished sixth in her first outing of the season.
Fujii wins battle for bronze
In a thrilling contest for third, Fujii clung on in the bronze-medal position, cheered on by flag-waging spectators as she entered the National Stadium with Torres close on her heels.
With two red cards to her name, the 26-year-old was in danger of losing it all had she picked up a third and been forced to endure a two-minute penalty.
In the end, Fujii just held on to finish a hair ahead of Torres in their shared time of 1:26.18, a Japanese record.
“I have been waiting for this moment for a while and it finally happened,” said Fujii, who was wearing a black ribbon to honour her coach, who died last month.
“Winning the bronze medal in my country feels very special.”