The visitors looked to be cruising thanks to goals from Lin Gao (13), Cleo (32) and Huang Bowen (68), but Yang Zi struck after 74 and 86 minutes as Hangzhou threatened a comeback.
Guangzhou held on for the points though to move clear of nearest challengers Jiangsu Shuntian, who could only manage a goalless draw at Liaoning.
Beijing Guoan fell 12 points behind the leaders with a heavy 4-0 loss at Shandong Luneng. Wang Yongpo and Lu Zheng scored two goals each to secure the points.
Henan Jianye remain at the foot of the standings following a 2-1 defeat at home to Dalian Aerbin.
Peter Utaka and Zhou Tong gave Aerbin a cushion with Leandro Netto's reply coming too late for Henan.
Qingdao Zhongneng failed to improve their lowly standing, going down 2-0 at Shanxi Zhongxin following goals from Nascimento Anselmo and Jailton Paraiba.
Dalian Shide eased past Guangzhou 4-1. Adriano's opener for Shide was cancelled out by Davi, but the home side responded with further strikes from Martin Kamburov, Park Donghyuk and Adriano.
The match between Tianjin Taida and Shanghai Shenhua finished goalless.