The warmth was on show again yesterday as Xi toasted the Prime Minister with a "Gambai".
It was another sign that strong and warm relationships do matter to Xi. And that he is prepared to invest in them.
But at the core, the Chinese President is deeply strategic in his approach to New Zealand.
Xi has recommitted China to working with New Zealand to increase our bilateral trade by 50 per cent by 2020 to help underpin this country's economic future; quelled fears that Australia has stolen a march against our dairy exporters and painted a picture of broader co-operation between friends.
It's not just good news on the economic front.
NZ will continue to be a source of high-quality protein for years to come. The economic relationship is broader than a dairy story - something which Xi emphasised with his urgings to New Zealanders to look to areas where China now wants to go in its own development, such as science and environmental technology to name just two.
But the charismatic Xi also demonstrated an acute appreciation of New Zealanders which started with his "open letter", published in the Herald on the eve of his visit.
"New Zealand is a shining pearl on the Pacific Ocean, a country blessed with a hardworking, courageous and warm-hearted people, a dream place of idyllic beauty, and a land of abundant resources that are much favoured in the global market," Xi wrote as he talked of a better future for China-New Zealand relations.
It's fair to say that Ambassador Wang Lutong - one of the new school of Chinese diplomats - would have had some input into the drafting of the letter and the sentiments expressed within it. It would have also been at the heart of why Xi praised Labour for its trail-blazing when he met leader Andrew Little.
The Chinese embassy is known to have been concerned at the stoking of anti-China sentiment at the beginning of the recent election campaign.
But while the President's public presence was restrained (no strolls on the waterfront or having his photo taken in a field with "beautiful cows" like his predecessor Hu Jintao in 2003), the visit was carefully crafted to send some important messages.
A case in point is the New Zealand free-trade agreement.
NZ was the first developed country to cement a free trade deal with China. This agreement has been a source of pride for New Zealand politicians. It has been trumpeted by their Chinese counterparts as among the many "firsts" in the relationship. At an economic level it helped pave the way for this country to quadruple exports since it was signed in 2008.
That leadership position was also the springboard for our dairy exporters to flourish against their Australian competitors.
But on Monday the chess table was suddenly slanted in Australia's favour.
Australian politicians have been quick to rub it in that their dairy exporters are now in a better position that their Kiwi competitors.
It's a mark of Xi's understanding of the Kiwi psyche that he moved fast to promise Key that China will upgrade our FTA to ensure NZ is on the same level playing field with Australia when it comes to the dairy trade.
This was the standout factor for Key from the Chinese President's three-day visit. The two leaders have now deputed Chinese Commerce Minister Gao Hucheng and Trade Minister Tim Groser to make sure the upgrade is made.
The challenge to New Zealand will be to keep pace with this fast-moving economic giant.
The metrics are overwhelming. Just take the 500 million Chinese tourists who Xi expects will be travelling outside their country within a decade. The presidential invitation is there. New Zealand will continue to benefit from Chinese tourists if it can scale up to meet demand. It's not a bad problem to have and underscores that this is an exciting time in the relationship.
