By reaching the Nedbank Cup final, Siwelele now stand a chance of playing in the second tier African club competition if they manage to beat Mamelodi Sundowns.
"I'm very happy for them because they've been doing well," Tignyemb tells snl24.com/kickoff.
"Now Celtic is a big team and they must show it in Africa. And I'm sure if they get an opportunity to do so, they will compete. Celtic are a good team.
"I can't go into their internal problems but they do have good players. I'm sure they can make it. To be a champion you don't need sangomas hey! You need a human being with two legs like us. They can easily reach the finals."
Tignyemb was in goal in the 2012 Telkom Knockout final when Celtic beat Sundowns with a goal that many still believe did not cross the line.
"What was the final score? Didn't Celtic win 1-0? So the ball crossed the line," he insists.
The 35-year-old, who has been training on his own since being released by Chippa United, says it is too early for him to quit playing.
"You know I've got 317 or 320 games now in the PSL. I want... I'm going to make it 400," he declares.
"But by the grace of God hey, because you can say something but God decides otherwise."