Iran, joint favourites with the Koreans, also advanced as group winners despite being held to a goalless draw by bitter rivals Iraq, while Kyrgyzstan squeaked through on their tournament debut.
Hwang Ui-jo and Kim Min-jae were on target as South Korea, boosted by the arrival of their talisman, ran China ragged in Abu Dhabi.
Son won the penalty converted by Hwang and fizzed in the assist for Kim to help South Korea finish top of Group C with a perfect nine points as they look to end 59 years of Asian Cup hurt.
"Of course I'm a bit tired -- I didn't expect to play for so long," Korean captain Son told AFP after completing 87 minutes despite a punishing run of 13 games for Tottenham since the start of December.
"But it's an honour to wear this red shirt and play for the national team. My first game of the tournament, clean sheet, 2-0 -- it's a happy afternoon!"
Marcello Lippi's China finished as group runners-up having likewise already sealed their place in the last 16 by winning their first two matches.
Spurs forward Son, who played in the London club's 1-0 defeat by Manchester United three days ago, showed quick feet to tempt China defender Shi Ke into a rash lunge after 12 minutes.
Hwang calmly tucked away the spot-kick to send thousands of Korean 'Red Devils' fans wild at the compact Al Nahyan Stadium.
South Korea, who beat Asian Cup first-timers Philippines and Kyrgyzstan 1-0 in their opening two games, went for the jugular.
A Hwang Hee-chan rocket forced China goalkeeper Yan Junling into a fingertip save before Hwang Ui-jo curled an effort against the post.
The Koreans doubled their lead six minutes after the break when Son's corner was met by Kim's thumping header.
Son went down clutching his ankle after a meaty challenge from China's tattooed defender Zhang Linpeng late on.
But the 26-year-old appeared to suffer no lasting damage and was given a rousing reception when he trotted off three minutes from time.
- Title drought -
South Korea, who famously reached the World Cup semi-finals in 2002, have failed to win Asian football's most coveted prize since winning back-to-back titles in 1956 and 1960.
But the addition of the mercurial Son has clearly energised the 2015 runners-up, who suddenly look a very different proposition.
China, Asian Cup finalists in 1984 and 2004, began the competition by edging Kyrgyzstan 2-1 and overpowering the Philippines 3-0.
But they were no match for South Korea, who are yet to learn the identity of their next opponents.
"Let's be honest, the Korean team is much stronger than us -- they're faster, technically superior and play with greater intensity," shrugged Lippi, whose side face Thailand in the last 16.
"We have to accept that and focus on our next challenge."
Iran, themselves looking to end a 43-year title drought, fired blanks in Dubai but still topped Group D on goal difference from Iraq after earlier thrashing Yemen 5-0 and beating Vietnam 2-0.
"When it's necessary for my players to play, they play," said Iran coach Carlos Queiroz.
"When it's necessary for them to fight, they fight. If it's necessary for them to sing and dance, they will be ready."
Elsewhere, a Vitalij Lux hat-trick sent Sven-Goran Eriksson's Philippines crashing out and Kyrgyzstan through from Group C as one of the best third-placed teams after a 3-1 victory.
The Filipino "street dogs" grabbed a late consolation through Stephan Schrock -- their first-ever Asian Cup goal and one celebrated with gusto by their noisy fans.
Vietnam eased past war-torn Yemen 2-0 to keep their hopes alive after a brilliant Nguyen Quang Hai free-kick and a penalty from Que Ngoc Hai.