When Neymar raced clear of Japan's backline to net his second of the night in Brazil's 4-0 win at Singapore's National Stadium, assistant referee Lim Kok Heng was ready to flag offside for the goal.
"I had doubts of him being offside when he received Philippe Coutinho's through ball," said Lim, 39, who has been running the lines for 12 years, three of which as a Fifa assistant referee.
"But in that split-second, I remembered something I learnt from an AFC (Asian Football Confederation) refereeing course - that you shouldn't make a decision if you are not sure."
Fortunately, video replays vindicated the Singaporean's decision, which nearly wiped one of his four goals and angered the Barcelona star's legions of fans.
That close call aside, the quartet of Singaporean match officials who took charge of the sold-out clash between Brazil and Japan night - referee Ahmad A'Qashah, assistant referees Lim and Ong Chai Lee and fourth official Sukhbir Singh - had a good night in the office when the match flowed without controversy. It was also the biggest game they had officiated in their careers as men in black.
All four have officiated at high-profile games at club level - like the AFC Cup and AFC Champions League - and international level but none of them could compare to the clash between the Samurai Blue and the Selecao.
Referee Ahmad, 27, a physical education teacher who has been a referee for eight years, said the experience had been "a dream come true".
Prior to the game, the group studied video footage of matches involving Brazil and Japan to help them understand more about the two teams.
"Watching their matches allow us to understand their style of play and anticipate what a certain player may do, thus decreasing the risk of flagging for a wrong decision," said Ong, 35, a civil servant who has officiated for six years, one of which as a Fifa assistant referee.
Even then, there are still close calls that one can never fully prepare for, like Neymar's second goal.
"This just goes to show that being a referee is not easy," said Lim.
The action wasn't just confined on the pitch, as fourth official Sukhbir could attest to.
"At one point during the game, Brazil's coach Dunga came up to me and made his feelings known about Neymar being on the wrong end of several fouls," said Sukhbir, who has a decade of refereeing experience under his belt.
"I told him we'll take note of it, and he went back to sit down. Sometimes, coaches just want to let out their frustrations or know that someone is listening to them."
Ahmad also believes that no preferential treatment is served to the stars of Japan and Brazil, saying: "I give every player the same treatment whether he is Neymar or an S-League player, and not based on his stature.
"I wasn't intimidated by the thought of not giving Neymar a free-kick if he wasn't on the end of a foul; they may be stars but we have to treat them equally."
Added Lim: "When the teams stepped out on the pitch, we see them as team yellow against team blue, not Brazil versus Japan or, say, Argentina versus England.
"You can be Neymar or Messi but if you are offside or commit a foul, then you're wrong. We won't and can't let it go just because of your stature."