The three flips were a success, but his landings were not quite steady, so Xavier covered his face with his left hand out of shyness and went to his father's side.
In response, Li laughed and patted the boy on the shoulder to encourage him.
The series of lakeside pictures-including the image capturing the boy's moment of shyness-went viral on leading news portals and social networks in both countries.
On his Chinese microblog and Twitter accounts, Trudeau posted another lakeside picture taken by a photographer behind the two couples to include the lake in the foreground, and so did not include the children and the trampoline.
But Chinese netizens did not forget Xavier.
"Your son is so great!" said @Youkemanmianbao.
"Your son's covering his face is very cute, and he surely will be a celebrity in China," said @BaiyanlangV106.