Overall, she has won 27 WTA Titles, nine in singles and eighteen in doubles. In singles, Petrova has reached a career high ranking of World No. 3 in May 2006 and has reached the semi-finals of the French Open in 2003 and 2005. In doubles, she won the year-ending Sony Ericsson Championships in 2004 with Meghann Shaughnessy. As of 4 July 2011, Petrova will be ranked World No. 33 in singles and World No. 10 in doubles.

Petrova was born in Moscow. Her parents were both very athletic – her father Viktor was a leading hammer thrower, while her mother Nadezhda Ilyina won a bronze medal at the 1976 Montreal Olympics in the 400 meter relay. Both her parents are still athletics coaches. As a child, Nadia did a lot of travelling around the world with her parents. She eventually settled in Egypt, where she trained with Mohammed Seif and her parents. Petrova states hard courts as her favourite surface, however, she has been most successful on clay courts. She is currently coached by Vladimir Platenik.

Petrova is an all-court aggressive player who is capable of hitting winners off both wings, but particularly off her back-hand which is considered to be one of the best in the women's game and which she is capable of hitting flat and with slice. Petrova's serve is considered her biggest asset and is one of the strongest on the women's tour along with the Williams Sisters and Samantha Stosur. In 2009 she hit the second most aces on the tour with 306, just behind Serena Williams and won over 72% of her service games. As an accomplished doubles player, Petrova's volleying skills are considered exceptional and she is not afraid to come into the net to finish off points. Petrova's main weakness is her movement around the court as she is often slow to retrieve balls and can sometimes struggle to defend well during rallies. Also, her forehand is sometimes erratic and can produce many unforced errors. Petrova states hard courts as her preferred surface, however, she has been most successful on clay courts where she can dictate play easier.