Mitch Marsh opens up about his emotional return to Australia after his grandfather's death just days before he scored an incredible 177 at the ODI World Cup

Mitch Marsh has opened up about saying goodbye to his grandfather - before returning to India and producing the performance of his life against Bangladesh in the ODI World Cup.

Marsh was very close to his 'Pop', who watched every match the Perth born star was a part of.

The 32-year-old flew to Western Australia recently to say his final farewells, before watching the funeral on a live stream on the insistence of his 'Nonna', who told Marsh to 'go straight back and get stuck in.'

Marsh duly delivered on the grand stage, blasting an unbeaten 177 from 132 balls in a brutal innings which included nine sixes.

He was also very grateful after coach Andrew McDonald and captain Pat Cummins gave him their blessing to briefly return home.

'The fact that Ronnie [McDonald] and Patty [Cummins] allowed me to go back, putting our family first, it meant a lot to me,' he told cricbuzz.

'Sitting with my grandma, watching the boys wear black armbands [against England]...little things like that, sometimes it goes unnoticed on TV.

'I told the boys I was coming back to win the World Cup.'

Nursing a heavy heart, Marsh returned to the subcontinent and was ushered back into the XI to face the Tigers.

Australia had already qualified for the semi-finals, but Marsh was in no mood to be rested.

Following the early dismissal of Travis Head, Marsh was sent in at the Maharashtra Cricket Association Stadium in Pune and quickly got to business.

Eight of Marsh's nine sixes came over either the straight field or deep mid-wicket, and tellingly, he also did it against both pace and spin. 

He looms as a key figure in the semi-final against South Africa, who will be nervous given Australia have won seven matches in succession.

Play begins at Eden Gardens in Kolkata from 7.30pm AEDT on Thursday, with the winner to face India in the final on November 19.