Hong Kong (CNN) Everything seemed to be going so well between China and the US.

After a successful visit by US President Donald Trump to Beijing earlier this year, relations with Chinese leader Xi Jinping appeared to be at an all time high, with both lauding each others' achievements and Trump saying he didn't blame China for "taking advantage" of previous US administrations.

But Chinese hopes this could represent a major shift in relations were dashed Monday when Trump labeled the country a "rival power" seeking to "challenge American influence, values and wealth."

A new document outlining his presidency's National Security Strategy (NSS) went even further, describing both China and Russia as "revisionist powers" who want "to shape a world antithetical to US values and interests."

Speaking Tuesday, Chinese foreign ministry spokeswoman Hua Chunying urged the US to "abandon its Cold War mentality and zero-sum game concept," warning failure to do so "would only harm itself as well as others."

"China will resolutely safeguard its sovereignty, security and right to develop," she said. "No one should have the fantasy of expecting China to swallow the bitter fruit of harming its own interests."

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Competition

Zhang Baohui, a professor of political science at Lingnan University in Hong Kong, said the document showed the partnership between Trump and Xi, which Beijing had been trying to cultivate, "is dead."

"China has invested huge diplomatic capital in securing that relationship," Zhang said. And the two leaders appeared to be getting along well during Trump's Beijing trip.

While in the Chinese capital, he showered Xi with praise , and was himself treated to a "state-visit plus," including a rare dinner in the Forbidden City.

While concrete wins were scant for both sides, the visit helped cap a supremely successful year for Xi , who has cemented his power over the country and the ruling Communist Party, and seen his global influence grow significantly since Trump's election.

It also provided some short term successes for Trump, who returned to Washington with a swath of trade and investment deals, and positive international press coverage.

A large part of the Trump-Xi relationship had been predicated on China's efforts, much touted by Trump, in solving the North Korea crisis.

But despite promises from both sides that progress was being made, Pyongyang has not shown any signs of bending to Chinese pressure (or American), and North Korea conducted its most sophisticated intercontinental ballistic missile (ICBM) test late last month

"Competition with China is here to stay," Van Jackson, a senior lecturer in international relations at Victoria University of Wellington, New Zealand, wrote Tuesday

"(The NSS) moves away from the false cooperative-competitive equivalency of past US administrations and embraces the latter as a reality that has been thrust upon America."

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US and China on 'collision course'

The failure to get Beijing to play ball on North Korea is similar to how the US has failed to get Chinese buy-in for international institutions and regulations, particularly on trade and intellectual policy -- where significant gaps remain, much to the chagrin of US companies

This has been a major issue for repeated administrations in Washington, Richard Haass, president of the Council on Foreign Relations, said during a talk Monday

"(The NSS) seems to reject the idea that we could embed China or Russia in an international system based on rules more or less to our liking," he said. "So it seems to suggest that the future is one of balance of power, friction, and so forth."

Haass added there appears to be a "reorienting of the relationship more towards the direction of China as something of a problem or a competitor, particularly in the economic realm."

According to Zhang, this is more of a return to the norm for US-China policy, after Trump appeared to consider taking a more isolationist approach in line with his "America First" campaign rhetoric.

"Now his foreign policy (is returning) to the standard posture of the US in world affairs since 1945, which is that it is bent on maintaining primacy and sees other great powers as challengers," he said.

This will likely represent a maintaining of the status quo in terms of US-China relations, Zhang said, pointing to the hard line the Obama administration took on the South China Sea and the consistently tough stance Trump has taken on trade since he came to power.

The new national security strategy, Zhang said, "shows that the two countries are on a long-term collision course."