Per protocol, Fernandes will now have until noon local time on Friday – the day of the fight – to pass his hydration test and make weight. If he fails to do so, his bout with Lineker (34-9) will either be renegotiated as a catchweight, with Fernandes losing a percentage of his purse, or cancelled outright.

The latter outcome would be a significant blow as the pair’s fight was already postponed from a February event when Lineker tested positive for Covid-19, while Fernandes has had to wait since October 2019 for a fight.

ONE Championship: Nguyen admits ‘I just need to win’ at Lights Out

Featherweight champion Thanh Le and challenger Garry Tonon, who will battle for gold in the card’s main event, both ultimately passed their hydration tests and made weight.

But American BJJ star Tonon (6-0) had some issues in the morning, turning up last without a hydration test sample, and stepping onto the scales fully clothed in sweatpants and a hoodie.

“I know I’m at least a kilo over right now,” he told competition director Ric Auty, who was conducting the official weigh-ins. “I’ll just weigh in like this. There’s no point in me weighing in and breaking the heat seal right now.

“Yeah, you’re overweight, Garry,” Auty said, after Tonon weighed in.

“No way, with all the sweats on and everything?” Tonon replied, jokingly. But the 30-year-old had no issues when came back at 4pm, and was in good mood at the evening’s ceremonial weigh-ins.

“In jiu jitsu, sometimes they call me the slippery salmon,” he told ONE ring announcer Dom Lau, who was emceeing the event. “I’m pretty tough to get a hold of, I’m pretty tough to catch. So I think he’s [Le] gonna have a tough time getting a hold of me with his fists. Thanh Le leaves missing one of his limbs.”

Those words brought a smile from 36-year-old Vietnamese-American Le (12-2).

“I like the confidence, I like the spryness,” he told Lau after his face-off with Tonon. “Obviously, I think it’s gonna go the other side of the coin, and I think he’ll be asleep at the end of this.

“I’m as prepared as I have ever been for any aspect in that ring, and if and when it gets [on the ground] I think he’ll be in for a good surprise. But before we get there I’m gonna have a little something waiting for him. I think we go fourth round, right leg, knockout.”

Six other fighters, including debuting Ukrainian featherweight Kiril Gorobets, failed their pre-fight hydration tests on Thursday morning. But by the time the ceremonial weigh-ins had concluded at Singapore Indoor Stadium in the evening, all but Fernandes and Argentine strawweight kickboxer Milagros Lopez had their hydration levels in check.

Chan Rothana and Kim Kyung-lock missed weight, and like the fighters who failed their hydration tests, will have until noon tomorrow to hit their contracted weights.

Complete ONE: Lights Out weigh-in results:

Strawweight kick-boxing (125 pounds)

• Milagros Lopez – 125 pounds (failed hydration)

• Lin Heqin – 124 pounds

174-pound catchweight Muay Thai

• Kim Kyung Lock – 177 pounds (missed weight)

• Liam Nolan – 174 pounds

Strawweight Muay Thai (125 pounds)

• Daniela Lopez – 125 pounds

• Iman Barlow – 124 pounds

Flyweight MMA (135 pounds)

• Eko Roni Saputra – 135 pounds

• Chan Rothana – 141 pounds (missed weight)

Strawweight kick-boxing (125 pounds)

• Josh Tonna – 125 pounds

• Zhang Peimian – 124 pounds

Strawweight MMA (125 pounds)

• Alex Silva – 125 pounds

• Adrian Mattheis -125 pounds

Heavyweight kick-boxing (265 pounds)

• Ismael Londt – 265 pounds

• Iraj Azizpour – 263 pounds

Featherweight MMA (155 pounds)

• Martin Nguyen (155 pounds)

• Kiril Gorobets (155 pounds)

Bantamweight MMA (145 pounds)

• Bibiano Fernandes – 147 pounds (missed weight and failed hydration test)

• John Lineker – 143 pounds

Featherweight MMA (155 pounds)

• Thanh Le – 153 pounds

• Garry Tonon – 155 pounds

Two title fights

Fernandes first got his hands on ONE gold in 2013. He retained the bantamweight title until 2018, when he lost to Kevin Belingon via split decision, but he reclaimed it in an immediate rematch and has held it ever since.

His 31-year-old opponent Lineker, earned his shot at Fernandes with impressive wins in his first three ONE fights: a decision win over Muin Gafurov, then back-to-back stoppages over Belingon and Troy Worthen.

Featherweight champ Le will be making the first defence of his title, which he won after knocking out Australia’s Martin Nguyen in late 2020.

Tonon earned his shot at gold with a decision win over former title challenge Koyomi Matsushima.