Mamelodi Sundowns and Orlando Pirates have one specific quality that is vastly superior to African champions Esperance, according to Tunisian football expert Souhail Khmira.
Esperance remain on course for an historic defence of the CAF Champions League this season and face off against Congolese giants TP Mazembe in the last four.
En route to the business end of the prestigious club comeptiton, the 28-time Tunisian champions lined up against Pirates in Group B and face the prospect of potentially meeting Sundowns in the final.
This is something the only unbeaten side remaining in the competition is wary of, according to Khmira, who witnessed the key strengths of the Absa Premiership title challengers first hand over the past few months.
"When Orlando Pirates came here to play in Tunisia, I was called to be their translator and interpretator, someone from Esperance called me and asked if I could help them out in terms of communication during their stay," the BBC correspondent tells KickOff.com.
"So I spent thrre days with them and what I noticed, I went to their practice sessions and everything and what I can say about Pirates and Mamelodi Sundowns from what I've seen is the players are in incredible physical shape; South Africans and South African teams, I'm not gonna lie, they are in great shape - even like size-wise, their endurance and stamina. The players have no problem going the full 90 minutes.
"With Tunisian players, not just Esperance, this is Tunisian players in general, they're not buff or very strong players, they struggle to maintain the same level during a game; the performance peaks at some point but they never have a consistent rhythm of performance.
"But with Sundowns and Pirates they keep a constant performance and pace throughout the game, they are very good physically and they are tactically gifted as well."
Esperance face off against Mazembe on 27 April at the Stade Olympique de Radès for their first-leg tie of the semifinal, while Masandawana will be in action a day before away to Wydad, unless CAF grants Sundowns their request to move the game to the 27th.