However, Tietjens belives there is a lot of hard work needed from the string of 15s players that have joined the squad for the Wellington leg of the series.
Apart from Williams, All Black Liam Messam, Hurricanes loose forward Ardie Savea, Auckland’s Ben Lam and brothers Rieko and Akira Ioane are other 15s players that have linked up with the the team.
“He’s really nervous but that’s exciting for him,” Tietjens told stuff.co.nz.
“It’s not going to happen in the first tournament that he plays in. You’ll see some lovely qualities and you’ll see some areas where he may get exposed and we all understand that, but I’m confident he has what it takes to be a fine sevens player.
“With Sonny it’s about learning what makes a good sevens player, getting an understanding of the rules, the patterns of play, the lines he needs to run and the defensive areas, because to be good at sevens you need to be a good defender.
“You’re accountable for all those things, plus you get a lot more attacking options. You’re going to be touching the balls a hell of a lot more than in fifteens.
“The big challenge in our game is decision making and that’s where you need to understand the game.”
New Zealand Sevens squad: Kurt Baker (Taranaki), Sam Dickson (Canterbury), Akira Ioane (Auckland), Rieko Ioane (Auckland), Gillies Kaka (Hawke’s Bay), Ben Lam (Auckland), Tim Mikkelson (Waikato), Augustine Pulu (Counties Manukau), Ardie Savea (Wellington), Regan Ware (Waikato), Sonny Bill Williams (Counties Manukau), Joe Webber (Waikato)