The Spanish giants will arrive in South Africa on Wednesday morning, play the Brazilians in the evening and jet out of the country immediately after the game at the FNB Stadium. Kick-off is at 18h15 in Johannesburg.
Barca will have little or no time at all to acclimatize to the weather in South Africa, but whether or not that will affect their preparation for this game remains a big topic.
However, Sport Scientist Dr Khatija Bahdur says the issue of altitude is unpredictable, and that it is not a foregone conclusion that it will have an impact on Barcelona players on the day.
Bahdur hinted that the fact that Barcelona may opt to use every member of their travelling squad for the game against Sundowns may be the only way to get the better of the altitude in South Africa.
"There is no way to predict the effect that the altitude will have," Bahdur told Goal.
"Some players might be affected more than others but performance wise, given the fact that the coach has implied that players won't be made to play the whole game means that the effect on performance should be minimal," she said.
"One of the ways of minimizing the impact of altitude is arriving as late as possible and competing close to time of arrival," explained Bahdur.
"This means that there is less time for physiological decrement (decrease in physiological performance) to set in," she added.
"However an important factor is how much time there is between time of arrival and competing at altitude and this optimal time would vary according to each individual. A team like Barcelona might have some information about how some of their players are affected by altitude (although it would be higher) since South American players are exposed to altitude," concluded Bahdur.