Thousands of people took to the streets of Hanoi late on Monday night to celebrate an otherwise minor event in international football - a 1-0 victory over Syria in the quarter-finals of the Asian Games in Indonesia.
"I'm so pumped up, I kept crying all night long," football fan Nguyen Hoang Ha posted on Facebook. "Thank you Mr. Park Hang-seo."
A second Facebook user was more effusive.
"Park Hang-seo is Vietnam's soccer wizard. He changed players and predicted the game so sharply," Nguyen Son wrote.
Another of their compatriots added wistfully: "I just wish wizard Park Hang-seo sensei was Vietnamese."
Park may be South Korean but he has given football-mad Vietnam, which has never qualified for the World Cup as a unified nation, its first taste of success on the international stage.
When he led Vietnam to the final of the under-23 Asian Cup in January, hundreds of thousands of people took to the streets of Vietnam's cities to wave flags and toot horns in jubilant scenes reminiscent of a revolution.
Those scenes were repeated on Monday night when Park's side beat Syria to earn the unified nation's first Asian Games semi-final, spurring calls for the 59-year-old to be granted Vietnamese citizenship in return for his coaching prowess.
In a cruel test of his patriotism, Vietnam's semi-final will be against South Korea.
"Everyone knows I love my hometown, and I love my nation. But I am currently the head coach of the Vietnam team," Park told reporters after Monday's game.
"We want to beat South Korea and get into the final".
RICE NOODLE HIDDINK
Park's success has been followed closely from Korea, where football fans have joked that he has "done enough" and should "stop winning" to pave the way for a Korean victory.
He has earned the nickname "Ssal-dink" in Korean, which translates as "Rice Noodle Hiddink" and is derived from a blend of the names of a popular Vietnamese dish and national hero Guus Hiddink.
Dutch coach Hiddink, with Park as his assistant, led South Korea on a fairytale run to the semi-finals of the 2002 World Cup, which the nation co-hosted with Japan.
Vietnam has ordered police and military forces in the capital, Hanoi, to prevent big gatherings or protests during its National Day on Sept. 2, the Hanoi People's Committee said on Monday.
But football celebrations threaten to scuttle those plans. A sea of fans waving Vietnamese flags rode on top of cars, motorbikes and even tractors and an ambulance after Monday's victory, such is the national excitement.
And for South Korea's Son Heung-min, the stakes for Wednesday's semi-final are even higher: Korean law states that every able-bodied man must report for national service for 21 months before their 28th birthday.
Aged 26, time is fast running out for the Tottenham Hotspur forward to gain the exemption offered to all Olympic medallists or Asian Games champions.
"We wish our boys a great performance, cool heads, and warm hearts," Vietnam football fan Khanh Duy Phan wrote on Facebook.
"And we hope Son Heung-min enjoys his military service."
(Additional reporting by Khanh Vu, editing by Nick Mulvenney)
