It was Xi Jinping's first trip as head of state to the perennially volatile Korean peninsula, and his second summit with Park, who visited China last year.
North Korean leader Kim Jong-Un is still waiting for an invitation to Beijing - a calculated rebuff that speaks to the strained relationship between Pyongyang and its historic and most important ally.
"No previous Chinese leader has put South Korea before and above the North like this," said Aidan Foster-Carter, a Korea expert at Leeds University.
In what some saw as a display of pique at Xi's visit, North Korea conducted a series of rocket and missile launches over the past week and pledged further tests in the future.
And Pyongyang scored a diplomatic victory of its own on Thursday, as Japan announced it was revoking some of its unilateral sanctions on North Korea after progress in talks on the Cold War kidnapping of Japanese nationals.
Japan and North Korea do not have formal diplomatic ties, and the announcement by Prime Minister Shinzo Abe is a significant step forward for a relationship that has been testy for decades.
After their talks, Xi and Park were expected to sign a joint communique, with Seoul hoping for a strong statement on North Korea's nuclear weapons program.
But analysts said Beijing was unlikely to up the rhetorical ante by any significant degree.
"That would go against China's traditional diplomatic pattern," said Kim Joon-hyung, professor of politics at Handong Global University.
"Xi will probably keep to the general line of urging the denuclearisation of the Korean peninsula, rather than criticising the North directly," Kim added.
As the North's diplomatic protector and chief economic benefactor, China has repeatedly been pressured by the international community to use its leverage to rein in Pyongyang's nuclear ambitions.
But while Beijing has become increasingly frustrated with the North's missile and nuclear tests, it remains wary of penalising the isolated state too heavily.
It is especially anxious to avoid any regime collapse that would result in a unified Korea with a US troop presence on its border.
Washington has played up Xi's two-day visit as evidence of Pyongyang's deepening diplomatic isolation.
"The symbolism of a visit by a Chinese leader to Seoul against the backdrop of tensions between North Korea and its neighbours ... is pretty striking," US Assistant Secretary of State Daniel Russel told AFP.
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