He had hoped to use an extra day's rest to recharge his batteries and reignite his assault at this year's Swimming World Championships, but the plan backfired for Joseph Schooling yesterday.
The 22-year-old narrowly missed out on a spot in the 100m freestyle semi-finals, after he finished 17th overall in the morning's heats.
Ironically, this will mean that he has an extra - and unplanned - day today to prepare for tomorrow's 100m butterfly, his pet event.
Having more time may sound helpful, but for Schooling, the restless racer par excellence, it was unproductive. He said: "It was a pretty rough morning, not going to lie. I had the whole day off, sitting in my hotel room for 24 hours.
"First race after that definitely felt pretty rough. It was hard to get the wheels turning.
"I thought I had a solid race, I'll need to see my splits to see where I was at."
He had clocked 48.86 seconds in heat 10, well below his national record of 48.27 set at last year's Rio Olympics where he qualified for the semi-finals, and was provisionally seventh with two more heats to go.
As he stood in the mixed zone, water dripping from his hefty body, he would repeatedly stop in mid-sentence to watch the last two heats unfold on the TV screen.
You can't take your mind off anything at any given second. You can relax, you can unwind, but it always has to to be in the back of your head.
JOSEPH SCHOOLING, who is learning his lesson that he needs to swim his perfect race.
After the 11th heat, he was in 11th place and seconds after Serbia's Velimir Stjepanovic touched the wall in 48.80 in the final heat, Schooling was left to deal with a surprise elimination.
He said it was a learning experience, noting to himself not to "sit until six o'clock and then catch the 6.05pm bus to come here and swim", in what amounted to his main physical activity on Tuesday when he attended training.
He added: "You can't take your mind off anything at any given second. You can relax, you can unwind, but it always has to to be in the back of your head."
The decision to withdraw from Tuesday's 200m fly heats was taken weeks back as Schooling and his team felt it was better to focus on the 50m fly, 100m free and the 100m fly, in which he is the reigning Olympic champion.
Schooling finished fifth in the 50m fly finals on Monday, 0.11 off a podium finish but setting an Asian record with his 22.93 effort during the semi-finals.
He said: "The key is to keep moving. After the 50m fly final, I kind of sat around, maybe took my mind off swimming a little bit, just sat in my room and watched water polo on TV.
"There were some positives from that, and some negatives. I'm not too worried. It's a good wake-up call and I'll be ready for my next one."
Despite some mixed performances in Budapest, the Singaporean is still among the favourites for the 100m fly. He won a bronze in the 2015 edition in Kazan, Russia, and owns the fastest time (50.39) in a textile suit, set when he won the Rio Olympic gold.
Schooling had targeted two world titles - in both the fly events - in Hungary and waved off suggestions that the pressure had increased ahead of his final event.
"No, this (100m fly) is the race I've been focusing on. I'm pretty comfortable and confident to be honest," he said.
"I'm happy this race is coming up. It's the one I've been anticipating the most and I think it'll be my best one. I'm pretty confident of that."
The assurance was clearly still there, although Schooling has left himself with plenty to ponder.