In a release, Sharapova said she got the idea after an undisclosed trip to Lai Thieu early last year where she said she saw many people playing tennis but couldn't understand why they were playing without a ball while using mosquito-catching rackets.

"They love tennis but they are poor and can't buy balls," Sharapova was told by an interpeter.

Later, she sent a letter to the Vietnam Tennis Federation saying that she would build the Sharapova Bangky tennis training center.

Earlier this week, she also became Sony Ericsson Mobile Communication's first global ambassador after signing a six-year. $88 million agreement with the company's design team to produce a range of products and accessories for the women's tennis tour, which is sponsored by Sony Ericcson.