Adam Peaty sensationally lowered his own 50m breaststroke world record twice in one day at the FINA World Championships, becoming the first man to break the 26-second mark in the process.
Peaty, the Olympic 100m breaststroke champion who won the world title over that distance on Monday, caused a stir in Tuesday's morning session in Budapest when he improved on his previous record 50m time of 26.42 seconds by a considerable margin, clocking 26.10secs in a heat.
However, the Briton was not finished there and went faster still in his subsequent semi-final, winning in a stunning time of 25.95secs.
Even Peaty himself seem shocked to dip under 26 seconds, the 22-year-old mouthing "no way" and smiling broadly upon seeing his time.
In a post-race interview with the BBC, Peaty insisted he was determined to find further improvement, with the final of the 50m breaststroke to come on Wednesday.
"This morning I went 26.1 and I thought 'it's going to be hard to beat that'," he said.
"I can't believe it, I can't even think. I'm just looking for areas now where I can improve."
Former Olympic champion Rebecca Adlington, working as a pundit on the BBC, said of her compatriot: "I think he shocked himself. It was the first time in a long time I've actually seen him genuinely shocked.
"He still has room to improve that - that is what is insane."