Momota was comfortably leading 13-6 when he returned a shot that never came back, as Rhustavito slumped to the floor in agony and had to be taken off the court in a wheelchair.
For Momota, Rhustavito’s unfortunate mishap meant he progressed the furthest this season.
“I had no confidence stepping to court on my current form. But I have now qualified to the last four, and that should give me some confidence. The Malaysian fans have been excellent too, and I am really encouraged by their support,” he said.
The world number two seemed to be enjoying the support at the Axiata Arena, as he lapped up the rapturous ovation after overcoming Angus Ng Ka Long in a tense encounter on Thursday.
Momota would be hoping to reproduce some of his best form when he faces three-time world junior champion Kunvalut Vitidsarn in the semi-finals on Saturday.
Viktor Axelsen meanwhile continued his fiery form as he came from a game down to beat Anthony Ginting 18-21, 21-17, 21-12.
The world number one later said he felt like a spring chicken after the 65-minute success.
“Today was a really close game, and I think it’s about small periods during the sets which makes the biggest difference. I don’t think the score does justice to the game.
“It was a really intense game. I’m happy with how I managed to play and come out on top,” said Axelsen, who faces Jonatan Christie of Indonesia next.