European under-23 champion David Omoregie ran his quickest time as he reached the final of the 110m hurdles at the Anniversary Games.
The 19-year-old from Cardiff shaved five-tenths of a second off his previous best, finishing third in his heat in a time of 13.50 seconds.
The Welshman was last in the final won by Jason Richardson in 13.19 seconds.
"I can't believe it, I'm so shocked," said Omoregie, who claimed his European title in Estonia in June.
"Everybody else's PBs were so much faster than mine - I can't believe it to be honest."
The races were run in poor conditions, with heavy and persistent rain making things difficult for the runners.
However, Omoregie said he didn't let that bother him.
"It was wet, but I was just so focussed on my race," he added.