With or without a trade deal, US-China relations are destined to deteriorate as they enter an era of increasingly nationalistic rivalry in the diplomatic and economic arena, according to analysts.
The United States faces a growing challenge to its lone superpower status from a Communist-ruled China whose global influence, military might and high-tech capabilities are rapidly rising.
The toughening stances on both sides in their trade war showed that the two powers are ready to play hardball to protect their national interests.
President Donald Trump followed through Friday on a threat to target all remaining Chinese exports with tariffs, then warned Saturday any trade deal would be "far worse for (China) if it has to be negotiated in my second term".
Beijing said it would make no concessions on core principles, even as the two sides eye more talks.
There are many other sources of tension ripe for flare-ups: US military aid to self-ruled Taiwan, Chinese territorial claims in the disputed South China Sea, US criticism of Beijing's Belt and Road global infrastructure programme, and US security warnings against Chinese telecom champion Huawei.
"US-China relations are continuing their steady deterioration, which I think is an inevitable consequence of national interests that are starting to overlap and bump into each other and cause friction," said Jonathan Sullivan, a China specialist at the University of Nottingham.
"Despite the Trump wild card factor, I would suggest that the current trade war is a symbol of things to come."
- Clash of civilisations -
The downward spiral coincides with increasing top-level nationalism in both countries.
Xi touts his "Chinese dream of national rejuvenation" -- a return to the nation's former glory -- which sounds like Trump's "Make America Great Again".
The director of policy planning at the US State Department, Kiron Skinner, raised eyebrows last month when she described the rivalry as a "a fight with a really different civilisation and a different ideology."
Skinner put it in racial terms, telling a security forum the China was first US "great power competitor that is not Caucasian".
Chinese foreign ministry spokesman Geng Shuang hit back, calling it "absurd and utterly unacceptable" to look at bilateral ties "from a clash-of-civilisations or even racist perspective."
The trade war is stirring nationalist sentiment in China.
"Objectively, trade war has unprecedentedly mobilized hostility between Chinese and American societies toward each other," the editor-in-chief of China's nationalist Global Times tabloid, Hu Xijin, wrote on Twitter on Saturday.
"I am very worried the mutual hostility could spiral out of control, causing a big retrogression of the entire international relations."
The trade war has made "many more people in China, not just the paranoid cadres, but a much broader swath of the elite and population realise or believe that America's goal is to keep China down," said Bill Bishop, publisher of the Sinocism China Newsletter.
Beijing could attempt to harness nationalism in the trade war, he added, though it is a "double-edged sword" that could spiral out of control.
"There's a pretty deep wellspring of anti-foreign, anti-American sentiment," Bishop told AFP, which could trigger consumer boycotts of US goods or even protests, like those that followed the 1999 US and NATO bombing of the Chinese embassy in Belgrade.
"We've yet to see any real significant news for boycotts of American goods," he said, "but that's something that's in the toolkit."
- 'Key is high-tech' -
The two countries are also locked in a battle for global influence, with Washington calling Xi's cherished Belt and Road Initiative -- a project to connect Asia, Europe and Africa via a network of ports, railways and roads -- a "vanity project".
On the military front, China is rapidly modernising its army with big spending on aircraft carriers, stealth warplanes and other state-of-the-art weaponry.
Even if China and the US sign a trade agreement, competition will remain "fierce and frequent", said Hua Po, a Beijing-based independent political commentator.
"The US's concerns about China are well-founded," Hua told AFP. "Even though China is still a developing country, it is working hard to catch up to the US."
Technology has taken centre stage in the battle for economic supremacy.
One company, Huawei, is in the middle of the skirmish as it seeks to become the global leader in ultra-fast 5G wireless technology.
The United States has pressed Western allies to shun Huawei over fears that its equipment can serve Chinese intelligence services, and a top executive was detained in Canada on a US warrant over Iran sanctions violations.
"The trade war has little to do with surplus and deficit," said Shi Yinhong, a professor at Renmin University's School of International Relations.
"The key is high-tech," he said, adding that the trade dispute is also a way to "force China to change many parts of its economic system and industrial policies."