Chinese football authorities included the 30-year-old in the national side last month in a bid to improve their chances of qualifying for the 2022 tournament in Qatar and Elkeson lived up to expectations by netting two penalties late in the Group A match at the Rasmee Dhandu Stadium.
Despite its clout as a global sporting and financial power China have qualified for the World Cup only once, leading to a change in policy that now allows naturalised foreign-born players to play for the national team.
"We want to go to Qatar (2022 World Cup)," Chen Xuyuan, new president of the Chinese Football Association (CFA), was quoted as saying by state media last month.
"Naturalised players can be helpful in order to achieve the national team's short-term goals.
"Up to now, clubs have registered nine naturalised players with or without Chinese heritage at the CFA in total, some of them are still going through the naturalisation process."
China dominated the game and were 2-0 up at half-time with Wu Xi and Wu Lei finding the net in the 34th and 45th minute, respectively.
They then won three straight penalties, with Yang Xu first scoring from the spot in the 65th minute before Elkeson made his mark with seven minutes remaining and claimed his double in stoppage time to complete the rout.
Earlier, Hong Kong fans booed their own national anthem and sang in protest against Beijing's rule as months of political unrest spilled onto the football pitch in a 2-0 defeat to Iran.
The ear-splitting disgruntlement all but drowned out "March of the Volunteers", the anthem the semi-autonomous territory shares with mainland China, at what was Hong Kong's first home game after a summer of upheaval.
Fans also sang a newly composed protest song, "Glory to Hong Kong", repeatedly chanted "Liberate Hong Kong" and waved a black version of the territory's Bauhinia flag, a symbol of the protests that have gripped the city for 14 weeks.
Elsewhere, Australia thrashed Kuwait 3-0 with Mathew Leckie scoring twice, South Korea beat Turkmenistan 2-0, Thailand smashed Indonesia 3-0 and the UAE edged past Malaysia 2-1.