It was just the latest display of elaborate pageantry put on by his Chinese hosts, and inside the cavernous state edifice two hours later, the outsized display of flattery appeared to pay off.
"I give China great credit," he added. "In actuality, I do blame past administrations for allowing this trade deficit to take place and grow."
Trump reaffirmed his position Friday morning, tweeting: "I don't blame China, I blame the incompetence of past Admins for allowing China to take advantage of the U.S. on trade leading up to a point where the U.S. is losing $100's of billions. How can you blame China for taking advantage of people that had no clue? I would've done same!"
It was a remarkable show of deference to Xi, who emerged from last month's Communist Party Congress the most powerful Chinese leader in a generation. And while US officials downplayed the significance of the remark, it nevertheless laid bare the lengths to which Trump is prioritizing his personal chemistry with his counterparts here as he seeks to advance an agenda of isolating North Korea and brokering new trade deals.
Trump's praise for his Chinese counterpart wasn't limited to the remarks at the signing ceremony for the $250 billion in US-Chinese business deals. At the top of a bilateral meeting, the accolades dripped from Trump's mouth as he expressed his gratitude for the welcome mat Xi had laid out.
They had an "absolutely terrific" dinner. It was a "very, very great honor" to be together. The military display was "magnificent." And their relationship? "A great one."
Trump did not avoid pointing out China's "unfair trade practices" and its "theft of intellectual property," but his conclusion that the imbalance in the US-Chinese trade relationship was the fault of his predecessors ignored the role of China's system of state-run enterprises and limiting market access policies.
'Tongue in cheek'
Trump's discussions with Xi yielded no immediate signs that the structural changes needed to rebalance the relationship were coming.
Trump's absolution of Chinese blame on trade matters, a day after the anniversary of his election, were a stunning statement from the man who vilified China at every turn during the presidential campaign, accusing the country of having "raped" the US and branding it as an "economic enemy."
Trump has held few consistent positions on policy issues during his decades of flirtation with a presidential run, but his stance on China has long been a notable exception.
His long-held view of China as an economic boogeyman became a central part of his "Make America Great Again" campaign platform that promised a rebirth of US manufacturing.
"We can't continue to allow China to rape our country and that's what they're doing. It's the greatest theft in the history of the world," Trump told a campaign crowd in May 2016.
But Trump's heavy-handed criticism of China was often also mixed with a similar dose of criticism for US officials, whom he accused of getting outmaneuvered by Chinese negotiators.
"You can win against China if you're smart. But our people don't have a clue. We give state dinners to the heads of China. I said why are you doing state dinners for them? They're ripping us left and right. Just take them to McDonald's and go back to the negotiating table," Trump told a crowd in the first summer of his presidential campaign.
While Trump publicly took a more conciliatory approach to China, several thousand miles away in Michigan, his former chief strategist, Steve Bannon, carried forward the mantle of Trump's past criticism, warning that the country is a "dictatorship that sees us as an enemy to be defeated."
With that backdrop, it remains unclear how Trump's more measured approach to his old campaign trail villain will go over with his base, including those blue-collar voters in Michigan who are counting on Trump to take a hardline against China -- and are still listening to Bannon.
Trump's formula
So far, it appears Trump's formula for winning against China amounts to excessive praise and, at least publicly, absolving China of blame for its role in crafting policies that have disadvantaged the US.
Trump also avoided putting his host in an uncomfortable position, making none of the demands his past three predecessors have made that Xi take questions alongside him from independent journalists.
Touring Asia this week for the first time, Trump has found plenty of leaders willing to satisfy his craving for praise. Facing political headwinds back home -- including sagging approval ratings, an investigation into his campaign's ties to Russia, and this week a resounding defeat for Republicans in state elections -- Trump has basked in the thrall of making new friends.
In Tokyo, Trump was greeted by custom hats ordered up by Prime Minister Shinzo Abe that read "Donald and Shinzo: Make Alliance Even Greater." The two men signed them with markers as reporters looked on.
Two days later in Seoul, the President's campaign slogan surfaced again.
"President Trump's election victory one year ago is already making America great again," President Moon Jae-in announced during a toast ahead of a state dinner.
From Riyadh to Paris to Beijing, world leaders have consistently returned to Chapter 1 of the Trump textbook as they prepare for a visit from Trump: flattery will get you everywhere.
Whether he's being feted by sword wielding dancers or reviewing rows of French troops, Trump has relished formal state welcomes and the importance they confer upon him as he jets aboard Air Force One to global capitals.
Even before Trump took office, his eye toward a presidential reception proved unsparing. When President Barack Obama was denied a set of carpeted air-stairs from which to descend Air Force One at the start of last year's G20 talks in Hangzhou, China, Trump declared at a campaign rally that such an indignity wouldn't happen on his watch.
"If that were me," Trump said, "I'd say, 'You know what folks, I respect you a lot, let's close the doors, let's get out of here.' "
When Trump arrived in Beijing on Wednesday, the stairs were there.