Wambach's goal was her 20th of the year. It's just the sixth time a U.S. women's player has scored 20 or more goals in a calendar year and makes Wambach the first player to do it twice.
Nicole Barnhart got the start in goal for the USA, her first match since July 2005.
Oct. 17 in Portland, Ore.
USA 4 Mexico 0. Goals: Lilly 45, Wambach 76, Kai 82, Lloyd 87.
USA -- Barnhart, Whitehill, Ellertson (Hucles, 34), Rampone, Boxx (Osborne, 46), Tarpley (Lloyd, 78), Wagner (Kai, 68), Chalupny, O'Reilly, Wambach, Lilly.
Mexico -- S. Perez, Sandoval, Gonzalez, de Jesus Castillo, Gordillo, Saucedo, Vergara, Lopez (P. Perez, 80), Padilla, Ocampo, Worbis.
Referee: Margaret Domka (USA).