South Africa and Zimbabwe. Over a period of time, the two nations have been known as the the the 'Big Brother' and 'Little Brother' in the cricketing landscape. Occasionally, the Little Brother (Zimbabwe) has turned out to be the better side, but with a 36-2 win-loss record in their favour in ODIs, the Big Brother (South Africa) clearly hold all the aces in the head-to-head battle between the the two teams.
ZIMBABWE TOUR OF SOUTH AFRICA, 2018
'Big Brother' South Africa target series win

South Africa pacers Lungi Ngidi and Kagiso Rabada shared five wickets between them in the first ODI. © AFP
South Africa continued to dominate the lopsided nature of the rivalry when they overcame Zimbabwe in the first of the three-match ODI series in Kimberley