Carrillo has stopped all five of his promotional opponents since joining ONE in 2023. His 28-4 career record includes a perfect finishing rate under the ONE banner, with his most recent victory coming via knockout of seven-time World Champion Sitthichai Sitsongpeenong at ONE Fight Night 30 in April.
The 27-year-old Glaswegian has prepared for this contest at Bangtao Muay Thai and MMA in Phuket, Thailand. His training camp has focused on adding new dimensions to his striking arsenal while maintaining the knockout power that has defined his ONE Championship tenure.
“I’m always in great physical condition for every fight,” said Carrillo.
“I train as hard as my body allows me to during every single camp. I don’t like leaving any stones unturned, and this camp is no different. The training camp has been absolutely fantastic.”
His move from bantamweight to featherweight has enhanced his performance significantly. Despite securing highlight-reel knockouts at 135 pounds against former ONE Bantamweight Muay Thai World Champion Nong-O Hama, Muangthai PK Saenchai, and Saemapetch Fairtex, his physical growth made the weight cut increasingly difficult.
Competing at featherweight has improved both his strength and speed. The elimination of weight cutting has allowed Carrillo to focus entirely on skill development and tactical preparation rather than managing his body weight.
“This camp has been a bit different from all the ones before,” he said.
“My first good fight camp was against Sitthichai. Now, this one just shows how much better preparations are now, without focusing too much on diet and losing weight and so on. I feel like I’m really made for this division. I’m much faster.”
Lessei presents a tactical challenge with his 4-inch height and reach advantage. The American’s dimensions could create problems for opponents who struggle to close distance effectively. But Carrillo has built his reputation on solving exactly these types of challenges, finding ways to get inside on taller opponents before unleashing devastating combinations.
His training camp has addressed specific weapons and techniques for this matchup, though Carrillo prefers to keep those preparations private until the opening bell. His confidence stems from the improvements he’s made at his natural weight class.
“I’m not going to give away the specifics that I have been working on throughout fight camp,” said Carrillo.
“But I’m confident that as soon as the first bell goes, you’ll see exactly what I’ve been working on because I’m gonna get right to that. My power is even better now, and that will be on display.”
