The Brazilians have only clinched the continental title once in 2016 under then coach Pitso Mosimane, with Mokwena as his assistant.
He says Downs will need more than just consistency.
"I think you need a lot of quality. You also need a lot of luck because I always say the league competitions are always about the best teams and the cream always rises to the top because you've got to be consistent over a period of six, seven, eight months maybe. But The Champions League and cup competitions need quality and good performances," Mokwena said.
Sundowns’ group also includes Egyptian giants Al Ahly and Coton Sport of Cameroon.
These different profiles require adequate preparations, the coach insists.
"As you come into the first leg, second leg you need a little bit of luck but you generate your luck with the work that you put in. It's a lot of hard work, it's not easy. You've got to watch games of the opposition because you don't know the players. It's different teams, coming from different parts of the continent. North African teams play different to the SADC (The Southern African Development Community) region teams, they play different to Central African teams," he added.
There’s a risk in the Champions League too that Al Hilal, for instance, could use a different team to the one Sundowns have done their homework on.
"The players have to understand that sometimes the footage that we give them from league competitions is not necessarily what you expect in the Champions League because they've got foreigners that they can register in the Champions League that they don't register in the domestic league," Mokwena explained.
Another key factor to take into account in the group stages is that the video assistant referee (VAR) system gets introduced at this phase of the tournament.
That technology is not yet available in the Premier Soccer League.
"You've got to have the mental fortitude to overcome the external factors that go from officiating with the assistance of VAR, something we don't have here in South Africa. That also has an influence on the type of football games that are played. The quality and surfaces of the pitches. The availability of flights and the traveling and all these other external factors," he concluded.