However, if you have been tracking Schooling's performances and timings over the past four years after the Rio Games, you could have seen this coming.
In 2017, the first threat to his title defence emerged at the World Championships. That was where Caeleb Dressel first announced his arrival on the world stage.
The American clocked 49.86s in the 100m butterfly final. Hungary’s Kristof Milak came after him in 50.62s. Schooling was third in 50.83s.
And since then, Schooling's times have been regressing. He won gold at the 2018 Asian Games in 51.04s. At the 2019 FINA World Championships, he clocked 52.93s in the heats and didn't qualify for the semi-finals. He was 24th out of 77 swimmers.
At the 2019 SEA Games, he finally clawed back to win gold in 51.84s.
But this year, at the ISCA International Senior Cup in Florida in March, Schooling clocked 52.93s again to finish second behind Dressel, who cruised in at 51.69s.
And so this much was clear as we approached the Olympics - Schooling was not going to win a medal, much less successfully defend his gold.
Perhaps, our sports officials knew it too but chose to be diplomatic.
At a press conference before the Olympics in early July, Singapore Sports Institute chief Toh Boon Yi said there were no medal targets for Schooling or any of Singapore's contingent.
"Joseph has already made history and this is something that nobody can take away from him," said Toh. "He will go down in history as that young man that won Singapore's first gold medal."