LOS ANGELES (AFP) - Aussie Samantha Stosur continued her impressive play at the Los Angeles Women's Tennis Championships on Friday, rallying to beat China's Zheng Jie 4-6, 6-3, 6-4 in the quarter-finals. Stosur, who is seeking her first career singles title, has enjoyed a good run of success the past few months, improving her world ranking to 18. Stosur moves on to the semis where she will face Romania's Sorana Cirstea who beat eighth seeded Agnieszka Radwanska 7-6 (7/4), 1-6, 7-5. "It's definitely a goal of mine to try and win a singles title," Stosur said. "I've been in four finals and lost every one of them in three sets. "My whole career I've been trying to become a better singles player. This year it's all just come together." Russia's Maria Sharapova also advanced to the semis, by beating Poland's Urszula Radwanska 6-4, 7-5. Sharapova will next face Italy's Flavia Pennetta who beat second seeded Vera Zvonareva 6-4, 6-2. The 13th seeded Stosur is known more for her talent in doubles but was knocked out of the hardcourt doubles draw on Thursday. Zheng's loss came less than 24 hours after she stunned top seed Dinara Safina in three sets on Thursday night. This is the second time Zheng and Stosur have met in singles this season with Zheng winning their last meeting at Dubai in February. Stosur saved five of eight break points and was good on 77 percent of her first serves in the two-hour match against Zheng at the Home Depot Center tennis facility in south central Los Angeles. Sharapova, who is recovering from major shoulder surgery, is starting to see the light at the end of the tunnel. "I made a lot more errors than I wanted to," she said. "In the second set, just kind of went off. "I created so many bad habits. Eventually it's going to work itself into place." Sharapova clinched the win on a challenge after her forehand to the corner was initially called long. She challenged and won to move on to play Pennetta. "Her second serve she was hitting 70 miles per hour and I was pounding on it," said Sharapova.