Salford centre Sa’u scored eight tries in nine matches for New Zealand from 2009 to 2010.
The Auckland-born outside back, who joined the Red Devils in 2013, was in the stands at the KC Stadium on Sunday to watch the first Test.
“I’ve got a couple of good friends there, Isaac Luke is one of my best mates,” Sa’u said.
“I went to support. New Zealand went pretty good in the first half.
“I thought second half we lacked direction.
“But we’ve got another big game coming up Saturday so if we get up then and come third game it’ll be a good match.
“I thought the boys went well. The boys who debuted were awesome.”
Sa’u is confident the current Kiwi team has enough quality to get the job done at the Olympic Stadium.
“One hundred per cent they can still get the win,” he said.
“I’m a proud Kiwi and I’m always supporting the boys.
“I know they’ll be working hard to try and prepare the best they can to get the win.
“It was awesome to see the brothers performing the haka, it gives you goosebumps and memories from when you used to play for the Kiwis.”
Sa’u and his Salford teammates will begin pre-season training for the 2016 Super League season on Monday.
“Not long to go, I’m just enjoying the last couple of days,” the 28-year old said.
“Once we start it’s pretty full on.”