Dikwena wrapped up their domestic campaign with a 1-0 win at SuperSport United last weekend, finishing ninth in the Premiership standings.
However, there is little time to rest as they are still competing in the Confederation Cup.
Johnson's men will face CS Sfaxien in Tunis on Sunday, having lost 4-2 to Swaziland's Mbabane Swallows after drawing 1-1 with Algerian side MC Alger in their Group B opener.
Sundowns have endured a punishing schedule in recent seasons owing to their exploits in Africa, and will continue the defence of their Champions League crown against Esperance at Lucas Moripe Stadium on Friday night.
Pirates, continental champions in 1995, faced similar challenges when they reached the finals of the Champions League and Confed Cup in 2013 and 2015 respectively.
"It’s a learning curve," Johnson told Stars' website.
"It’s something you have got to phone Sundowns and Pirates about and see how they tried to manoeuvre the off-season. You are going to see what you have got. You will see with your fitness people how you get it and maybe you get it right. We will see."
Johnson expects a tough encounter this weekend.
"We know they are a good team. They lost to MC Alger. We know the type of pitch they play on and the type of players they have. They are good technically. We are going to go out there and play the best we can. I have said to the players before. It’s about showing your talents and showing what you can do on the continent."