Ellertson, a defender in her previous 32 games for the USA, sat out for most of 2008 after having her second child. She was a forward in college at the University of Washington.
Ellerston's first international goal came in the 71st minute after USC senior Amy Rodriguez powered past Liu Hua Na into the left side of the penalty area, where she fed Ellerston with a perfect cross on the ground that eluded Chinese goalkeeper Zhang Yanru.
"I'm so excited, I'm grinning from ear to ear," said Ellertson. "I wanted to be back playing and being out there. Today was so awesome. It's been a while since I played up top but it felt great."
Veteran Kristine Lilly returned from a nearly 14-month hiatus after taking time off to have her first child. She earned her 341st cap when she came on in the 55th minute.
The victory was the USA's third over China this year after also winning 1-0 in January in Guangzhou and 4-0 in March at the Algarve Cup in Portugal.
The Achieve Your Gold Tour wraps up on Wednesday at Ford Field in Detroit as the USA hosts China again.
Dec. 13 in Carson, Calif.
USA 1 China 0. Goals: Ellertson 61.
USA -- Solo, Mitts, Rampone, Buehler (Markgraf, 46), Chalupny (Dalmy, 71), O'Reilly (White, 71), Boxx, Lloyd, Hucles (Lilly, 55), Ellertson (Cheney, 77), Tarpley (Rodriguez, 46).
China -- Zhang Yanru, Zhou, Weng Xin Zhi, Yuan, Liu Hua Na (Gao, 76), Wang Dan Dan (Zhang Ying, 68), Zhang Na, Bi, Xu Yuan (Liu Sa, 46), Han (Wang Kun, 80), Lou (Gu, 46).
Referee: Kari Seitz (USA).