David Smith survived a scare as he reached the BC1 semi-finals ©Twitter

Double Paralympic gold medallist David Smith survived a scare as he needed a tie-break to beat Japan's Takumi Nakamura to reach the semi-finals of the Boccia World Championships in Liverpool.

The reigning Paralympic champion squeezed through to the last four in the BC1 category following a nervy contest with Nakamura at the Exhibition Centre in the British city.

Smith, who also won team BC1-2 gold at the 2008 Paralympics in Beijing, eventually emerged victorious after the match had finished 3-3.

The result saw him continue his quest for the world title on home soil.

Smith will face Witsanu Huadpradit of Thailand, who thrashed Brazil's José Carlos Chagas de Oliveira 8-1, in the semi-finals.

The other last four encounter in the category will be between Daniel Perez of The Netherlands and Chinese player Kai Sun.

Perez edged Slovakia's Tomas Kral 3-1, while Kai impressed in an 8-0 demolition of Brazil's Guilherme Moraes.

Robert Mezik ensured Slovakia had at least one semi-finalist as he ousted Watcharaphon Vongsa of Thailand 3-1 to book his semi-final place in the BC2 competition.

Mezik is joined in the last four by Thailand's Worawut Saengampa, who defeated Nadav Levi 3-2 in a hard-fought match.

The Championships in Liverpool, which unsuccessfully bid for the 2022 Commonwealth Games, continue tomorrow.