Michael Sata, who was running for the presidency for the fourth time, received 43 percent of the vote, against 36 percent for incumbent President Rupiah Banda, whose party ruled the country for 20 years.
Friday morning, jubilant supporters of Mr Sata stormed the building of the Supreme Court, delaying the moment it opened.
China has invested over 3 billion USD in the Zambian economy in recent years, especially in its mines of copper, cobalt and coal. Chinese citizens have also settled in the country and now manage farms, restaurants, shops, hospitals and clinics of traditional Chinese medicine.
Mr Sata is extremely popular in the heart of the mining regions, which accused the Chinese managers to exploit their Zambian workers. He has already promised to restore a tax, abolished in 2009, 25 percent of the profits of the mines. However, analysts believe it will be essentially powerless against the economic power of China.
Last year the Zambian economy has experienced tremendous growth from 7.6 percent and 6.4 percent in 2009, thanks to the explosion in global copper prices. This among other things allowed the government to build 27 new hospitals and more than a hundred bridges.