The 29-year-old, whose right arm was amputated at the age of three months due to thrombosis, is her country's first para-athlete to take part in the Olympics.
"I have been trying to qualify for the Olympics for years. I knew it would be difficult because the competition is very fierce in Brazil," Alexandre told AFP.
"But I succeeded. I got here and today I am making a huge dream come true for me."
Alexandre took up table tennis at the age of seven.
Initially she found it difficult to serve with one arm, but she mastered the tricky skill of throwing the ball up with her left hand then serving with vicious spin.
"I managed to adapt after about a year. Now my serve is one of my strong points," said the Brazilian, who is also a gifted skateboarder and cyclist.
Alexandre is already a decorated Paralympian, winning silver at the Tokyo Games, but on Monday she had her first taste of Olympic action, taking on the powerful South Koreans in the team event.
The third-seeded Koreans saw off the Brazilian challenge but Alexandre was philosophical after the defeat.
"It's about showing that everything is possible, regardless of whether you have one arm or one leg," she said.
She thanked the French crowd for a rapturous reception, adding: "I am celebrating and I will celebrate for many more days this dream that I am realising today."
'Never give up'
Alexandre is not the only Paralympian to feature in the Olympic table tennis tournament. Australia's Melissa Tapper, whose right arm is paralysed, is competing at her third Olympics.
But it was Polish player Natalia Partyka who laid the ground, competing in both Olympics and Paralympics in Beijing 2008 and London 2012.
"She's a source of inspiration. She has inspired many people, not just me but also Melissa Tapper," Alexandre told AFP, adding that she watched YouTube videos of Partyka in action.
She sees herself as representing people with disabilities from her country and all around the world.
"I think it can open a lot of doors. Inclusion in the country can be improved. I think sport is a great way to make that happen," she said.
Alexandre credits hours spent on her beloved skateboard as critical to a sense of balance that has propelled her to the top in table tennis.
She has always competed against able-bodied athletes and says she has not experienced prejudice.
"In the street, at school, I never saw it (prejudice). That has helped me a lot," she said.
The Brazilian is in a rare position to be able to compare the Paralympics and the Olympics and acknowledges that the Olympics has a different vibe.
"The athletes, the competition, the way of thinking. It's all different. I think it's also because there is much more competition," she said.
While her Olympic dream is for now over in Paris, she can turn her attention to the Paralympic Games, which run from August 28 to September 8.
Buoyed by her Olympic experience, she hopes to clinch individual gold at the Paralympics.
"Never give up on your dreams," she said.
