The Glasgow centre led the Scots to a 57-17 victory over Fiji but he knows World Champions South Africa will present a huge challenge when they come calling to Murrayfield next weekend.
"It went probably better than I thought it was going to go, to be honest," Tuipulotu said about the Fiji game.
"That first 20 minutes, I thought we were going to be in a real arm-wrestle, but the boys really fronted up.
"I did say in the huddle pre-game how important that first 20 minutes were going to be, especially against Fiji, because they were going to come out after their war dance with their tails up.
"We talked about exiting cleanly after we scored points. We can't afford to do that next week.
"We've got to get our heads around our own game. The elephant in the room is that the world champions are in town next week and we get a free swing at them. It's a unique opportunity.
"It feels like the start of something new for me. To start as captain feels like a new start.