(CNN) -- Maria Sharapova continued her rehabilitation from injury with a comfortable victory at the L.A. Women's Tennis Championships on an opening day that saw early exits for three of the four seeded players in action.
Russia's Maria Sharapova is seeking to return to her best form after an injury-hit past year.
The unseeded former world No. 1 improved her record since returning from nine months out with shoulder problems to 14-5 as she crushed Australia's Jarmila Groth 6-0 6-4 on Monday night.
The Russian, who was blown away by Venus Williams in the quarterfinals at Stanford on Friday, will play third seed Victoria Azarenka of Belarus in the second round.
"She was swinging away all through the match and a lot of them started to go in, but she couldn't consistently do it," Sharapova told the WTA Tour Web site.
"Playing all of these tournaments is a great benefit for me. This is my sixth tournament back and this is going to be a process on things I want to improve and work on in my game. It has been a good ride so far."
Last year's losing finalist Flavia Pennetta also progressed, with the Italian 10th seed being taken to three sets by lucky loser Varvara Lepchenko.
Pennetta, beaten in 2008 by Dinara Safina, will next play American wildcard Coco Vandeweghe following her 6-2 5-7 6-0 victory against Uzbekistan-born, U.S. resident Lepchenko.
Pennetta let slip a 4-1 lead in the second set, but then lost only seven points in taking out the decider in just 23 minutes.
Vandeweghe defeated Italy's Tathiana Garbin 6-4 6-4 for her first victory in a WTA Tour main-draw match.
French 11th seed Virginie Razzano was beaten 7-6 (7-5) 6-3 by Russia's Anna Chakvetadze, who will next play unseeded compatriot Alisa Kleybanova.
Estonian 15th seed Kaia Kanepi suffered a 6-3 7-6 (7-4) reverse against Czech Lucie Safarova, who earned a second-round clash with Ukrainian Alona Bondarenko.
Pennetta's 16th-seeded compatriot Francesca Schiavone was dumped out by veteran American qualifier Jill Craybas, who won 7-6 (9-7) 6-2.
Craybas will next face Yanina Wickmayer after the unseeded Belgian crushed former teen prodigy Nicole Vaidisova of the Czech Republic 6-1 6-1.
The tournament field includes five of the world's top-10 players, including No. 1 Safina and her fellow Russian, second seed Vera Zvonareva.
Denmark's Caroline Wozniacki, Azarenka and Russia's Nadia Petrova, ranked 8-10, also received first-round byes.
The Williams sisters Venus and Serena are not playing, nor is Bank of the West Classic winner Marion Bartoli.
The Frenchwoman upset Venus in Sunday's final in Stanford, while world No. 2 Serena was beaten by Samantha Stosur in the quarterfinals.