Daria Kasatkina has won her first tournament as an Australian citizen.

Kasatkina, who became an Aussie citizen in January after switching allegiance from Russia, defeated her German opponent Tamara Korpatsch 2-6 6-3 7-5 at the WTA 125 Catalonia Open in Spain.

The victory comes after the 28-year-old dropped to her lowest world ranking in 11 years, ranked 75th heading into the tournament.

Kasatkina took to her Instagram to thank her fans for their support.

“Felt all the love and can’t describe how happy I am to lift this trophy after a long time of struggle,” she said.

“Thanks everyone for your support.”

Kasatkina dropped the opening set 2-6 before clawing her way back to win the second 6-3.

Despite being up 5-1 and with a match point in the final set, her opponent Korpatsch won the next four games to level the set at 5-5 before Kasatkina took the next two games to lift the trophy.

“It’s very tough to be honest because I was one point away from winning the match and then it’s 5-all,” she told tournament media post-match.

“It’s tough to not lose your mind in that moment. That’s sport and I’m really happy I was able to manage that because it’s been a very, very difficult moment.”