Off the football pitch it is a total mismatch: China's 1.4 billion population versus Guam's 170,000.
But the two collide in a World Cup qualifier on Sunday with the US island territory's squad -- which includes high-school and college players -- trying to cut their Chinese hosts down to size.
Guam will be massive underdogs and anything other than a Chinese victory in front of a sell-out crowd of about 30,000 in Suzhou would be a shock.
But Guam have done something similar before. In 2015 they stunned India -- which has the second-biggest population after China -- in World Cup qualifying.
It did not bring them a maiden World Cup appearance, but it lifted Asian football's smallest member association to 146th in the FIFA rankings. Guam are now 198th of 210 teams.
Underlining the scale of the task against China, Guam's comparatively miniscule population means the national side only has about 50 players to choose from, Guam Football Association president Valentino San Gil told AFP by telephone.
Of the current squad, a couple are in professional or semi-professional football in the United States, but most play in Guam's domestic league -- while juggling full-time jobs -- or college football in the US.
One of their players, Eduardo Pedemonte, will graduate from high school this year, and there are two sets of brothers.
The Western Pacific island may be a US territory but football, rather than baseball or basketball, is the most popular sport in Guam, said San Gil.
"Here we just play football year-round because our weather permits," he added, in a nod to the beaches and sun that make Guam a popular tourist destination.
- 'We were the punch bag' -
Guam has invested in its football infrastructure and also brought in coaches from abroad.
"That's why our football quality has improved over the years," said San Gil.
Guam are bottom of the qualifying group with five defeats in as many games and a goal difference of minus 17, and cannot qualify for the Qatar 2022 World Cup.
But while they could be said to have overachieved in the past, the opposite is true of China.
The Chinese have ambitions to win a World Cup but are 77th in the FIFA rankings and a distant second behind Syria in the group. Only the top team is guaranteed to reach the next stage on the road to Qatar.
As with many places that rely on tourism, the coronavirus has hit Guam hard.
Football is no exception, with domestic leagues suspended since March last year and the team losing "six or seven" players who backed out of the China trip because of pandemic-related travel and health requirements, said San Gil.
The depleted squad will be kept in a virus-secure "bubble" in Suzhou for matches against China, the Philippines and Syria.
Guam lost 7-0 to China earlier in qualifying and San Gil is not predicting an upset this weekend to rival the breakthrough victory over India.
But he is buoyant about the future of football in Guam, which only became a member of FIFA in 1996 and were beaten 19-0 by China in 2000.
"When we first started football we were like the punch bag," said San Gil.
"But we strived to do a lot better and we are actually now competing.
"The government here believes that there is good potential to compete against India, Turkmenistan, Oman... all the other countries."