Liverpool middleweight Anthony Fowler guaranteed a World Championships medal after another superb performance in Almaty, Kazakhstan on Wednesday.
Fowler outpointed Germany's Stefan Haertel in their middleweight quarter-final, gaining revenge for the defeat he suffered to the same opponent at the European Championships in Minsk in June.
It was the second successive world-class performance from Fowler, who had upset Ukrainian second seed Dmytro Mytrofanov in the previous round.
Fowler, who will box for a final place on Friday, said: "I'm on top of the world.
"I've been working hard day in, day out since I was 11 years old, and it was worth it for this.
"I'm not finished yet though - I want that gold medal and will be giving it everything."
Welshman Andrew Selby also guaranteed a medal after edging to a thin split decision win over home favourite Ilyas Suleimenov in the flyweight class.
But there was disappointment for Selby's Welsh team-mate, Olympic silver medallist Fred Evans, who dropped a unanimous verdict to Germany's Arajik Marutjan in their welterweight quarter-final.
Selby, who lost the world final by a single point two years ago, recovered from a sluggish start and saved his sharper work for the later stages as he earned the win by the narrowest of margins.
But hopes Selby could face Irishman Paddy Barnes in the last four were dashed when Barnes lost a scrappy contest on points to Uzbekistan's Jasurbek Latipov.
Double Olympic bronze medallist Barnes, who had moved up from light-flyweight for the first time, suffered a cut in the first round of a bout in which both men were deducted a point for infringements.
Reigning European middleweight champion Jason Quigley secured Ireland's first medal with a fine points win over Hungarian fourth seed Zoltan Harsca.
And light-heavyweight Joe Ward joined Quigley in guaranteeing a medal when he won his bout against Russian third seed Nikita Ivanov, who was prevented from continuing after sustaining a cut in the first round.
But heavyweight Tommy McCarthy lost a split decision to Argentina's Yamil Peralta, and Olympic bronze medallist Michael Conlan went down to tough Russian Vladimir Nikitin at bantamweight.