The visitors led twice in the first half and got within eight points of the Crusaders in the final 15 minutes of Friday's Super Rugby Pacific clash at the new One NZ Stadium, before falling 35-20.
It leaves them 4-5, on 19 points and in seventh place with five regular-season games to play.
The Crusaders played with passion in the stadium opening, 15 years after a deadly earthquake shook the city.
Coach Dan McKellar again lamented poor discipline that led to two costly yellow cards, but saw enough to give him hope the Waratahs can manufacture a top-six finish.
The return in Sydney of outside back Suaalii will help, the code-hopper set to return against the Western Force next week after a serious hamstring tear suffered in early March.
It sets up a juicy clash with Force recruit Lomax, who impressed in his starting debut last week, a defeat of the Crusaders, before a bye this week.
"Presence, leadership, his defence," McKellar said of what former NRL star Suaalii would bring.
"And to get him the ball in space ... a big, abrasive point of difference.
"He's a player we've missed. In the 23 games (we've played), he's played eight since he's been here.
"I hope we can turn that around to help us achieve what we want to achieve."
McKellar said fullback Max Jorgensen had passed his HIA after being forced off on Friday by a high shot from Crusaders captain David Havili that led to a yellow card.
