Wiaan Mulder is a cricketer who hasn't gotten a century in an ODI. His highest score in an ODI was 64 from playing 25 matches. On the other hand, he couldn't reach the figure of fift in his T20 career from playing 11 matches. But here we see his best score of 367 runs from Zimbabwe. Here is highlighted the quality of Zimbabwe's test career. How can he get these huge runs from Zimbabwe? The ICC should stop the test cricket performance of Zimbabwe.
I wouldn't say that he was able to score such runs as Zimbabwe was the opponent. Wiaan Mulder hasn't really played a great innings before this match. But we should judge him by observing his performances in the next few series. This match could be the turning point of his career. If he can't perform well in upcoming matches, then we can only say that he was able to score big as the opponent was Zimbabwe.
Wiaan Mulder is in the squad of South Africa as a
bowling all-rounder. His batting position was lower middle order in most of the matches (in all formats). You can't expect a lot of runs, fifties and centuries from such position.