Cape Town - Springbok prop Tendai "Beast" Mtawarira has apologised to Japanese opponent Keita Inagaki for his shocking spear tackle in Sunday's Rugby World Cup quarter-final in Tokyo.

Mtawarira lifted and drove Inagaki into the ground as early as the ninth minute of the Springboks' 26-3 victory.

Referee Wayne Barnes, without consulting the TMO, brandished a yellow card, sending Mtawarira to the sin-bin for 10 minutes.

Mtawarira was making his 100th Test start for the Springboks - and playing his 115th Test in total.

Many felt Mtawarira could consider himself fortunate not to have been shown a red card for his actions, especially in light of World Rugby's clampdown on foul play.

At the time of writing, World Rugby has not cited Mtawarira, freeing him to play in Sunday's semi-final against Wales in Yokohama.