The Chinese recorded an early 5-4 win over Switzerland and returned to the curling venue in the evening for an 11-7 decision over Germany.
Norway won its only game of the day, 8-5 over Germany, to get to 3-0 for the tournament.
Sweden fell out of a first-place tie by losing its only match of the day 8-5 to Denmark. The Swedes and Britain are tied for third at 3-1, Britain having fought off Switzerland 4-2 in its lone match.
The loss by Denmark left it at 2-2 for the tournament, tied with two-time defending champion Canada. The Canadians won their only match with a 7-4 decision over Russia.
The United States captured its first victory of the Olympics with a 9-5 victory over Denmark. Switzerland is 1-3 and both Russia and Germany are winless in four games.
A nine-game round-robin tournament will be played before the top four teams earn spots in the semifinals.