Buzarnescu made WTA qualifying debut at 2007 Fés. Introduced to tennis at age 4 by parents, she has been part of the Romanian national Tennis federation since 12 and grew up idolizing Pete Sampras and Monica Seles. After a long streak of injuries and a couple of knee surgeries, she considered to leave tennis and gained PhD in sports science from UNEFS in Bucharest. In 2015 she played team competitions in the Netherlands, finding pace and motivations., That year she won 48 matches, four ITF Circuit titles and rose over 600 places in the rankings, finishing at No.260.
In 2016 she posted a 9-11 win-loss record in 2016, with best result a QF run at $50k ITF/Hodmezovasarhely, finishing the season ranked No.351.
In 2017 she took three months off for surgery to her left wrist. She played her first Grand Slam main draw, losing to Caroline Wozniacki in her first match against a Top 50 opponent. In Linz, she lived her breakthrough tournament. She beat fourth seed Anett Kontaveit in straight sets before defeating Alja Tomljanovic and Belinda Bencic in three sets and reached the semifinal in her first WTA main draw appearance. She consequently became became the oldest player to make her Top 100 debut since Israel’s Tzipora Obziler in 2007.