Host South Africa meet Argentina in the final.
Tietjens described the injury situation as "quite unbelievable" saying they had been down to six-and-a-half fit players. Te Tamaki had been suspended for eight games on a dangerous tackle charge, but he would be available for the Wellington sevens in late January because the suspension would be served in prior domestic tournaments.
"It gave some young players and opportunity to grow," Tietjens said.
"It was a gutsy performance from the players - I'm proud of how they gutsed it out. But there were too many injuries.
"It showed that this game of Sevens is so so competitive now. You've got to be on your game and any team decimated from injury...the dynamic of the team changes."
Tietjens is looking forward to working with the 15s stars Liam Messam, Ardie Savea, Akira Ioane and Sonny Bill Williams. But his immediate concern is to get current sevens players such as Tim Mikkelson, Joe Webber, Scott Curry, Gillies Kaka and Regan Ware back from injury.
