Xi's speech to political leaders, chief executives and bankers at the World Economic Forum in Davos, Switzerland, was a first by a Chinese leader and marked a possible shift in the global political landscape as western democracies struggle with the rise of populist nationalism.
China, a one-party communist state that maintains tough restrictions on foreign investment, would seem an unlikely champion of free markets at an event that has become synonymous with global capitalism.
But with Trump promising a more protectionist, insular approach and Europe preoccupied with its own problems, from Brexit to terror attacks, China sees an opportunity to fill what could become a vacuum in global economic leadership.
Speaking before a vast audience that included US Vice President Joe Biden, Xi likened protectionism to "locking oneself in a dark room" and cutting off all "light and air".
"No one will emerge as a winner in a trade war," Xi said in the nearly hour-long speech.
Real estate mogul and former reality TV star Trump, who will be inaugurated as US president on Friday, campaigned on a promise to confront China more aggressively on trade and renegotiate or ditch multilateral trade agreements.
His entourage has accused China of waging economic war against the United States.
But Xi pushed back against the accusations of unfair trade practices, saying Beijing would not devlaue its currency for competitive advantage, as Trump has repeatedly accused it of doing in the past.
Xi also urged all signatories of a landmark climate deal agreed in Paris roughly one year ago to stick to the agreement, a clear message to Trump, who has criticised the deal and indicated he may pull the US out of it.
'LOOKING TO CHINA'
In a sign of China's ambitions, more than half a dozen senior Chinese government figures joined Xi in travelling to Davos in the Swiss Alps this week, a bigger and more high-level delegation than in previous years.
A large number of WEF panels are focused on Asia, including one entitled "Asia Takes the Lead".
"In a world marked by great uncertainty and volatility the world is looking to China," WEF founder and chairman Klaus Schwab said before welcoming Xi to the stage.
Xi's appearance comes at a time of rising tensions between Beijing and Trump, who broke with decades of precedent last month by taking a congratulatory telephone call from the president of Taiwan, which Beijing sees as part of China.
Last week Trump said America's "One China" policy was up for negotiation, triggering a furious response from state-run Chinese newspapers who said Beijing would be forced to "take off the gloves" if Trump did not change his rhetoric.
Although Xi painted a picture of China as a "wide open" economy, his government has come under mounting criticism from trading partners for its continued restrictions on foreign investments at a time when its state-run firms are aggressively pursuing acquisitions in Europe.
In an apparent nod to these criticisms, China's cabinet announced ahead of Xi's speech that it would take steps to ease limits on investment in banks and other financial institutions. But no further details were provided, nor a timetable for their implementation.
Some officials, speaking on condition of anonymity, suggested that China was simply manoeuvring to take economic advantage of what appearso be a growing divide between the US and Europe.
