"Exports continued to defy USA tariffs last month but imports struggled in the face of cooling domestic demand", said Julian Evans-Pritchard of Capital Economics in a report.
"With global growth likely to cool further in the coming quarters and USA tariffs set to become more punishing, the recent resilience of exports is unlikely to be sustained".
When Mr Trump then extended those tariffs to a further $200 billion of goods in September, Beijing promptly hit back with tariffs on a further $60 billion of United States goods.
China has responded by imposing counter tariffs, which the Trump administration alleges show political interference by targeting products from key states in next month's congressional elections.
Despite concerns from some officials about the yuan's depreciation, U.S. Treasury staff have not recommended labeling China as a currency manipulator in a coming report on foreign exchange rate practices, according to media reports on Thursday.
He blamed previous USA presidents for allowing China to pursue unfair trade practices and said he had to tell Beijing, "It's over".
The US tariffs cover a broad range of Chinese consumer goods, while China's were aimed mainly at American liquefied gas, machinery and electric equipment.
Li Kuiwen, a spokesman from the country's customs agency, also told reporters trade growth may slow somewhat in the fourth quarter.
The trade war entered a new level in September, with the United States imposing 10 per cent tariffs on US$200 billion worth of goods imported from China, effective as of September 24, which could escalate to 25 per cent in January 2019, while China fought back with tiered tariffs from 5 to 10 per cent on US$60 billion of USA goods.
Trump said the Chinese want to negotiate but he does not believe they are ready and he told them so.
Exports jumped 14.5 percent for September on-year, beating forecasts from analysts polled by Bloomberg News, while imports rose 14.3 percent on-year.
Imports rose 14.3 percent in September, versus a 19.9 percent gain in August, slightly missing analysts' forecast of a 15.0 percent growth. An official survey also confirmed a further manufacturing weakening.
But global trade would continue to face challenges as the U.S. It also slashed China's growth forecast for next year to 6.2 percent from 6.4 percent.