The Croatian Petra Martic began playing tennis aged 4 when her mother Sandra, a former handball player, introduced her to the game. She grew up in Split, living close to the coast, where she likes to return between tournaments to relax. A baseliner whose favorite shot is serve, Martic describes her game as aggressive.
She made her professional debut in 2005. A one-time WTA singles finalist, at 2012 Kuala Lumpur (ret. vs. Hsieh w/heat illness), and a four-time doubles runner-up, at 2012 Paris [Indoors], 2012 Bad Gastein, 2013 Marrakech (w/Mladenovic) and 2016 Monterrey (w/M.Sanchez), Martic has also reached four semifinals, at Bogotá (2011), Copenhagen (2011, 2012) and Rio de Janeiro (2016)
Martic climbed into the Top 100 for the first time on September 14, 2009 (after US Open; rose from No.137 to No.89) and enjoyed a Top 50 season in 2011, finishing at No.49.
In 2016 she won WTA 125K Series doubles title at 2016 Bol (w/Knoll).
In April 2017 she played her first event after 10 months out with a back injury, coming through qualifying to win the title at $25k ITF in Santa Margherita Di Pula. At Roland Garros that year, Martic notched the first Top 20 win in nearly five years over No.13 Keys in the second round. She followed that win by upsetting No.19 Sevastova and reached the Round 16 for the second time at Roland Garros: as a qualifier, she lost to Svitolina after leading 5-2 in final set. Martic was ranked No.290 during the campaign and became the lowest-ranked player to reach R16 at a Grand Slam since the unranked Henin finished R-Up at 2010 Australian Open (l. S.Williams). Since 1983, the only other player outside the Top 200 to reach R16 in Paris was No.279 Martínez in 1988. Following that exploit, Martic completed in 2017 her fourth Top 100 season.
In 2018 Martic completed her second Top 50 season finishing at a career-high No.32. She made the fourth round at Australian Open (l. Mertens) to open the season. She then posted her first quarterfinal finish of the year in Budapest (l. Kuzmova) and enjoyed a productive March, reaching the quarterfinals in Indian Wells (d. No.6 Ostapenko, l. Halep) and the third round in Miami (l. Barty).
On clay, she reached the second round at Roland Garros (l. Q.Wang), Madrid (l. Garcia) and Rome (l. Svitolina). After a disappointing grasscourt season marked by a first-round loss at Wimbledon (l. Makarova) she returned to clay to reach the second WTA singles final of her career in Bucharest (l. Sevastova).
She began the North American hardcourt season by reaching the second round in Cincinnati (as a qualifier, l. Anisimova). Then she fell at the first hurdle at US Open (l. Safarova). Following the final Slam of the season, she won the WTA 125K Series title in Chicago (d. Barthel) and reached the quarterfinals in Québec City (l. Pegula).
During the Asian Swing, she made the second round in Beijing, losing to Wozniacki: after that run, in 2018 she won at least one match at all four of the Premier Mandatory tournaments. In the final tournament of the campaign, she lost to No.16 Garcia in the quarterfinals in Tianjin.