Rollers beat Kampala Council City Authority (KCCA) 1-0 in Gaborone on Friday night, before Swallows held Zambian side Zesco United to a 1-1 draw in Ndola on Saturday.
Both Rollers and Swallows have qualified for the Champions League group stages for the first time in their history.
"We have newcomers that are blooming. Township Rollers are winning. We have got KCCA, we have got Swallows. They gave a scare to Zesco, they never sat back. It’s unbelievable,” said Mosimane.
"We need to give credit to Mbabane Swallows. When we saw them playing [Kaizer] Chiefs and [Orlando] Pirates two years back, you guys probably said that was just friendly games. They beat Pirates and Chiefs, you know the story. And they beat the team in Congo [AC Leopards]. We struggled against Leopards, [but] they beat them. You have to respect the new ones coming up. They will surprise you,” he added.
After dropping two vital points in a 1-1 draw at home against Wydad Casablanca at Lucas Moripe Stadium, Sundowns will be hoping to bounce back when they take on Guinea’s Horoya on May 22 in Conakry.