Hopes had been high that Singapore could carry their momentum from a successful SEA Games in June into this week's Fina World Championships.
However, fatigue has proved to be a major stumbling block for the Republic's swimmers.
This busy season, in which many of the 11-strong team have competed in four or more major meets since December, has taken its toll, said national coach Sergio Lopez.
Only butterfly specialist Joseph Schooling has advanced past the heats after three days of competition, while the rest of his teammates have struggled to keep up with the pace at the Kazan Arena.
Speaking to local media in a conference call yesterday, Lopez noted: "I didn't expect in a couple of races to swim the way we did... because the indications from training and everything make me feel confident we would swim better.
"But a lot of them have had to taper quite a few times and the SEA Games was a big ordeal for the team.
"It's not an excuse and it has been a learning experience for everyone and I'm still happy with our overall performance."
There have been positives, with Quah Zheng Wen breaking the national record in the 100m backstroke an encouraging sign at the nine-day meet in Russia.
As for Schooling, who was seventh in the 50m fly and just 0.1sec outside a podium finish, Lopez believes his charge has proved that he belongs on the world stage.
Not only was Schooling's time of 23.25sec a new personal best and a new Asian record, but he had also swum faster in each of his three races (23.40sec in the heats and 23.27sec in the semis).
This is in contrast to the same event at last year's Commonwealth Games in Glasgow, where he slowed with each race and ended the final seventh in 23.96.
Lopez said that this showed that Schooling, who turned 20 in June, is able to thrive under the pressure of a major competition.
The Spaniard added: "He's measuring up pretty well against the world's best. The 50m is a crapshoot. I wanted him to take just one breath but he had to take a second eight metres from the wall and only missed out on a medal by one-tenth of a second.
"He was upset after his race at not getting a medal but very mature in the way he reacted and realised how close he was. He's a fighter and won't give up and will learn from this experience.
"We still have 12 months to go to the Olympics next year and we will assess what needs to be done and to get Joseph in the best condition possible for Rio."