Kim Sang-sik and Nguyen Xuan Son: Is Vietnam's Title-Winning Formula Built to Last?

Kim Sang-sik and Nguyen Xuan Son: Is Vietnam's Title-Winning Formula Built to Last?

Hook

On the night of January 5, 2026, at Rajamangala Stadium in Bangkok, Nguyen Xuan Son lay on a stretcher with a broken leg. Vietnam still climbed to the ASEAN Cup title, but that moment exposed a paradox: what carried Vietnamese football back to the top of Southeast Asia came from two sources with no Vietnamese roots — a South Korean head coach and a naturalized Brazilian-born striker. I sat in Busan, watching the final on a screen, and asked myself: without Kim Sang-sik and Nguyen Xuan Son, where would this team stand?

The answer is not in the goals. It lies in how a football nation chose the shortest path to restore belief, while the roots of its problems were never touched. A Southeast Asian trophy can hide a great deal, but it cannot hide the question of the future.

Context

In early 2026, Vietnamese football hit bottom. In March 2026, two defeats to Indonesia in the 2026 World Cup qualifiers ended Philippe Troussier's reign — a coach expected to modernize the playing style, yet one who lost both results and the dressing room. The Vietnam Football Federation pivoted, and in May 2026 they chose Kim Sang-sik.

The name was no stranger to followers of Korean football. Kim Sang-sik is a former centre-back for the South Korea national team, part of the squad that reached the 2026 World Cup semi-finals on home soil. At club level, he led Jeonbuk Hyundai Motors to domestic honours before leaving the post. In other words, Vietnam did not hire a tactical revolutionary; they hired a tournament manager — the kind of coach who knows how to grind out points in short, tight matches with little space.

Vietnam had handed the top job to a South Korean before. Park Hang-seo led the national team from 2026 to 2026 and won the 2026 AFF Suzuki Cup. Two of Vietnam's three Southeast Asian titles have come under Korean coaches; the other, in 2026, belonged to Henrique Calisto, a Portuguese. Vietnamese football, whether it likes it or not, has tied its fate to the Korean coaching school.

Meanwhile, another story was taking shape. Rafaelson Bezerra Fernandes, a Brazilian striker playing for Nam Dinh in the V-League, completed his naturalization and became Nguyen Xuan Son in late 2026. He debuted for the national team just before the ASEAN Cup. In that tournament, Xuan Son topped the scoring chart and became the indispensable spearhead of Vietnam's attack.

Two pieces — a Korean coach and a naturalized striker — combined into Vietnam's Southeast Asian crown. But I do not believe in happy endings too easily. For someone who has followed Korean football for years, hiring a foreign coach and then winning is no miracle; it is a calculated choice.

Analysis

What matters is how Vietnam won, not just the trophy.

Under Kim Sang-sik, Vietnam played far more pragmatically than in the Troussier era. The team accepted ceding possession in safe zones, piling pressure into transitions and set pieces. Those are the fingerprints of Korean football: a disciplined block, tight distances between lines, and a target striker as an anchor. Nguyen Xuan Son was that anchor. He did more than score; he held the ball, drew centre-backs, and opened space for the runners behind him.

I watched Vietnam's matches at this tournament closely, and what struck me was not the goal count but the conversion rate. Vietnam did not create many chances per game; the team created few but sharp ones. That is the approach of a side that knows it cannot impose its game on equal opponents, so it chooses efficiency over flamboyance. Possession is the most deceptive metric in football; Vietnam won by refusing to fall into its trap.

On the bench, Kim Sang-sik showed the hallmarks of a coach schooled in the K League. He read the game in blocks of minutes, making substitutions to preserve structure rather than chase emotion. In tight matches, his team did not panic; they dropped deep, held their distances, and waited for their moment. That was the weapon Vietnamese football had lacked under Troussier, when the team tried to dominate possession but forgot how to defend.

Let me be blunt: that system stands on two pillars that could collapse at any time. The first is Kim Sang-sik, carrying Korean thinking and a Korean coaching network. The second is Nguyen Xuan Son, solving the scoring problem domestic football had struggled with for years. Xuan Son's injury in the final itself was a warning: when the only spearhead breaks, the whole system must switch to a contingency plan — and luck stood with Vietnam.

What stands out is that the goals did not come from individuals alone. In the final, Vietnam kept its structure and scored even after losing Xuan Son. That is a sign that Kim Sang-sik had installed a collective skeleton, not merely relied on one player's magic. With Xuan Son but without that skeleton, Vietnam could not have withstood Thailand's pressure.

Now look beneath the surface, at the domestic league. The V-League operates with a set quota of foreign players, and clubs still lean on foreign finishers to solve their scoring. The consequence is that domestic strikers are pushed to the margins, with fewer minutes and fewer chances to test themselves at the top level. When the national team needs a number nine, it must look elsewhere — or naturalize. Nguyen Xuan Son is the answer to a problem the V-League itself created.

This is what many overlook when praising the title. A football nation cannot use national-team success to paper over the weakness of its domestic league. Look at Thailand — the final opponent — and you see a football nation with a strong domestic league, home-grown players starting in key positions, and a properly funded youth system. Vietnam won that match, but with what? A foreign coach and a naturalized striker. That is a hard truth worth saying out loud.

I have watched many K League matches, and I know what makes a club sustainable. Sustainability comes from a system that can produce outstanding individuals, not from one outstanding individual. Kim Sang-sik's Jeonbuk won Korea's league not because of a single star, but because their entire league was strong enough to nurture victory. Vietnam does not yet have that foundation.

Contrarian angle

I could be wrong, and this is where I question myself.

There is another, more optimistic reading: the title proves Vietnamese football has the mettle to win a major tournament, that hiring a Korean coach was the right move, and that naturalization is a legitimate tool the whole world uses. Look at Indonesia with its naturalized squad, or at the Gulf football nations, and there is nothing shameful here. If so, Vietnam's success is a model, not an exception, and my scepticism is merely the perfectionism of an outsider looking in.

People hate me because I speak first, then come to me when I turn out right. This time, though, I am not sure I am right. Kim Sang-sik may be building something bigger than what I can see, and Nguyen Xuan Son may recover to carry the attack for a few more years.

Still, one point nags at me: a football nation cannot build a long-term strategy around a foreign coach and a naturalized striker. Kim Sang-sik will leave one day. Nguyen Xuan Son will grow older, and a broken leg at nearly thirty is a crack that heals poorly. When both are gone, what will Vietnam stand on? The answer lies in the V-League — where clubs still depend on foreign players to score, and where domestic strikers are pushed to the margins.

Referees are never wrong; the laws simply cannot keep up with the ball. Here, Vietnamese football's laws — from foreign-player quotas to youth development — cannot keep up with the national team's own success.

Takeaway

When the stadium falls silent, I hear the whisper of data most clearly. I do not need the whole world to nod; I only want someone to stop and listen. The 2026 ASEAN Cup is a proud moment, but it is a door opening into a room not yet built. Who won Vietnam the title is clear. What remains unclear is whether, once the roar fades, this football nation dares to look straight at the emptiness behind the trophy.