The 19-year-old battled to a 7-5 4-6 6-4 win in Thursday's quarter-final in Doha to snap twice Grand Slam champion Rybakina's nine-match winning run.
"Going into the match I knew it was going to be a really hard battle and I wanted to stay calm," said Mboko, who picked up her second victory over Rybakina in four meetings.
"I didn't really have that many expectations because she has a great record now, she just won the Australian Open. Going into the match I knew I had to play my 'A' game.
"I do understand that the higher profile players you play, you're going to have to raise your level."
Mboko started the 2025 season ranked outside the top 300 and is now 13th. She became the youngest player since Serena Williams to beat four major winners in a tournament en route to claiming last year's Canadian Open in Montreal.
Mboko plays former French Open champion Jelena Ostapenko in the Doha semi-finals later on Friday, where a win will confirm her top 10 debut on Monday.
"I'm expecting another hard battle," Mboko said.
"She knows these courts well and knows the environment. It'll be important to put up a fight."
Karolina Muchova takes on Maria Sakkari in the other last-four match-up.