On the second day of the Prime Minister's trade mission he welcomed the announcement of an £80 million investment in the manufacture of black London taxis in Coventry by Chinese car firm Geely, posed for a "selfie" photograph with Jack Ma, the creator of China's biggest online retail site, and hailed a treaty which will allow easier access for UK films to cinemas in a country which is opening new screens at a rate of seven a day. But it was the less than flattering assessment of Britain in the Global Times newspaper that created an undercurrent to the day. The paper's editorial questioned the "sincerity" of Mr Cameron's diplomacy amid ongoing anger about his meeting the Dalai Lama last year.
More cuttingly, it suggested China did not need better relations with the UK because it was now a diminished nation.
It said: "The UK is highly replaceable in China's Europe diplomacy. The UK is no longer any so-called 'big country'; it is an old European country suitable for travel and study abroad with a few good football teams."
Mr Cameron responded by saying: "I must have missed the bit about the football teams. I would just prefer to go on the figures.
"This is a visit that has delivered almost £6bn worth of deals. It is a visit that comes on the back of an 18-month period where we have seen more Chinese investment into Britain in the last 18 months than in the previous 30 years.
"And also it is a visit where we have seen very good, high-level, substantial discussions both with the premier and with the president - the premier who described the partnership as indispensable. So I will stick with the facts and the figures."
At Shanghai Hao Tong University, he sought to reassure students that there was no limit on how many Chinese students could study in the UK.
He also joked about the weekly "torture" of Prime Minister's Questions but stressed it was important to keep premiers "on their mettle".
At a lunch, he told guests how the Coalition was committed to working with China with "mutual respect and understanding" to deepen relations and remove trade barriers.
Mr Cameron rounded off his speech by attempting a phrase in Mandarin - "Wei shuang fang you li", roughly translated, "in both our interests".
Mandarin speakers in the audience described his pronunciation as good.