The former SA Schools captain is one of five players in the South African match-day squad who featured in last year’s World Rugby U20 Championship in Cape Town, where the Junior Boks finished third.

The other returning SA U20s from last year who will start against New Zealand are Asad Moos (scrumhalf), Jurenzo Julius (centre) and Litelihle Bester (wing). JF van Heerden (lock) was named amongst the replacements and is set to make an impact off the bench.

Porthen will anchor the front row alongside Ruan Swart (prop) and Juan Smal (hooker), while Thomas Dyer and Adam de Waal are the starting locks. The loose trio consists of flankers Sibabalwe Mahashe and Bathobele Hlekani, with Tiaan Jacobs at No 8.

In the backline, Moos got the nod a starting scrumhalf where he will partner flyhalf Tylor Sefoor. Bruce Sherwood and Julius will patrol the midfield, Bester and Joel Leotlela are the speedsters on the wing, and Michail Damon completes the backline at fullback.

Junior Bok coach Bafana Nhleko said his group had a good week training week in the build-up to the historic Sanzaar tournament.

“The medical and strength and conditioning staff did a sterling job to ensure our group settled in as quickly as possible after our long-haul flight from South Africa, and our preparations went well this week,” said Nhleko. “The players are now eager to put in a good effort on the field against a top-quality opponent.”

The rivalry and tradition between South Africa and New Zealand also mean a lot of pride are at stake in this opening-round encounter, but Nhleko also said his players have to be aware of the Kiwi threats all over the field.

“We all know about the tremendous rivalry, and the all-round threat of New Zealand is a well-known fact,” said Nhleko.

“Especially the physical battle will be huge between two teams that pride themselves on physicality. The main message has been to focus on ourselves and to drive our behaviours.

“So, as much as there is a lot at stake in this match and we are chasing a good performance, as a group, we are also eager to continue to learn and use this tournament as a great opportunity to further develop as a team.”

Hosts Australia and Argentina will clash in the other game of the opening-round double header. The new tournament comprises a round-robin format where all teams will play each other once and the top team after the three-round, six-match tournament will be declared as winner of the first U20 Rugby Championship.

The clash is scheduled to kick off at 09h00 (SA time, 17h00 in Australia) and will be broadcast live on SuperSport.

Junior Springbok team to face New Zealand:
15 Michail Damon
14 Joel Leotlela
13 Jurenzo Julius (vice-captain)
12 Bruce Sherwood
11 Litelihle Bester
10 Tylor Sefoor
9 Asad Moos

8 Tiaan Jacobs
7 Bathobele Hlekani
6 Sibabalwe Mahashe
5 Adam de Waal
4 Thomas Dyer
3 Zachary Porthen (captain)
2 Juan Smal
1 Ruan Swart

16 Ethan Bester
17 Mbasa Maqubela
18 Reno Hirst
19 JF van Heerden (vice-captain)
20 Thabang Mphafi
21 Ezekiel Ngobeni
22 Thurlon Williams
23 Joshua Boulle