"We had a long discussion already. So far, I have gotten nothing. Absolutely nothing," he said to laughs from the delegation.
"But I can see that, I think long-term, we are going to have a very, very great relationship and I look very much forward to it."
This is the first time the two leaders meet, after a US election that featured frequent barbs at China's "rape" of the US economy.
During that campaign Trump had ridiculed his predecessor's decision to offer Xi a coveted state dinner, saying that -- if elected -- he would serve the 63-year-old a Big Mac.
But inside Mar-a-Lago's ornate dining room -- with gold-trimmed chairs, fine cut glass and polished silverware -- it was Dover sole with champagne sauce and New York strip steak with whipped potatoes rather than McDonald's on the menu.
The open agenda and the personal setting for the 24-hour summit are designed to allow the leaders to freewheel and build a rapport, in what is the world's most important relationship.
Amid concerns about security and public perceptions, Xi and his wife are not staying at Mar-a-Lago, but at a resort and spa a short drive down the palm-fringed coast that is, for now, watched by snipers, tactical units and a coastguard cutter.
The two leaders were joined Thursday evening by US first lady and former model Melania Trump and Peng Liyuan -- a celebrated folk singer who Trump hailed as a "great, great celebrity."
Talks will continue up to a working lunch on Friday, and are likely to turn to more serious issues.
The summit has been somewhat overshadowed by renewed missile tests in North Korea and possible US military action in response to an apparent chemical attack in Syria.
The UN Security Council -- where both China and the United States hold a veto -- is holding crisis talks to discuss a response to Bashar al-Assad's Syrian regime.
Xi had arrived to the meeting with a gift basket of "tweetable deliverables," sources say, peace offerings on Trump's signature issues -- trade and jobs -- that he hopes will smooth over a relationship that began on shaky ground following disagreements over Taiwan.
There may also be offers to further open China's auto and agricultural markets, insiders say, and even some concessions on Chinese banks' transactions with North Korea, a vital financial lifeline for the country.
In return, Xi hopes to get assurances from Trump on punitive tariffs and that an American arms sale to Taiwan will be delayed, at least until after a major Communist Party meeting later this year.
Trump's position on democratically-ruled Taiwan, which China considers a breakaway province, has been a major irritant since the billionaire politician accepted a protocol-breaking phone call from the Taiwanese president after his election victory.
All politics is local
The summit stakes, both domestic and international, are high.
Disagreements over approaches to North Korea or bilateral trade could, if mishandled, destabilize North East Asia or tank the global economy.
On the domestic political front, Xi is heading into a critical year. Ahead of a party congress that could cement his grip on power for years to come, he needs to show that he can deal with the US leader as an equal.
He "cannot afford to lose face while China aspires to be the new center of gravity for the world order," China political analyst Willy Lam told AFP.
Meanwhile, Trump -- who is reeling from legislative defeats, low approval ratings and unrelenting scandals -- desperately needs a win.
On the US side, however, North Korea will likely top the agenda following Wednesday's provocative missile launch.
The Trump White House worries Pyongyang is just months away from marrying nuclear and long-range missile technology and putting the west coast of the United States within striking distance.
While Beijing has condemned the missile tests, it has hesitated to take dramatic action against Pyongyang, fearing that the country's collapse would generate a flood of refugees across its borders and leave the US military on its doorstep.
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