She won the silver medal at the Paris Olympics in 1924 in women's singles, losing the final to Helen Wills Moody.
Vlasto also won the version of the French national championships in 1924 that was open only to French nationals.
She was a doubles partner of Suzanne Lenglen in many doubles tournaments during the early 1920s.
According to Wallis Myers of the Daily Telegraph and Daily Mail, Vlasto was ranked in the world top ten in 1923 and 1926, reaching a career high of World No.
8 in those rankings in 1923.She married Jean-Baptiste Serpieri on 17 February 1927.