Faf du Plessis says South Africa can no longer afford to rest on their laurels when they take on New Zealand in a two-Test series, beginning on Friday.
Stand-in captain Du Plessis, replacing the injured AB de Villiers, leads his country in their first Test since England's tour concluded in January.
That series saw Alastair Cook's men triumph 2-1 and the Proteas have subsequently plummeted down the ICC rankings, heading into the opening encounter in Durban seventh in the standings.
Du Plessis conceded that South Africa had perhaps taken their place at the summit for granted and called for the squad to embrace the opportunity to represent their nation.
"We had a nice culture because we were playing well and then you can almost just leave it be," he said.
"Now, we want to challenge each other more and that goes right from the top, from the coaching staff to the guys carrying drinks on the field.
"We are trying to challenge each other more to be better and to not accept mediocrity. We have fallen in a few traps where we play so much cricket, you just rock up and play another game of cricket but playing for South Africa is a huge honour and it's about challenging each other to be better and to get back to being number one.
"We've got series at home now which can make a difference and which we will need to win. We've got New Zealand now and Sri Lanka later this year and in both those series, if we play well, we should win."
Defeat to England followed on from a chastening 3-0 loss in India at the end of 2015, and Du Plessis admitted that series had left its mark on the team.
"We suffered a bit; we had a few ghosts after the Indian series and that was most of the guys," he said.
"India was tough for us a batting unit and it left a few scars. Now it's a new season, we can focus on the strength of our batting again. The only way we can do that is by putting runs on the board."