Southby lamented the Ferns not being able to perform under pressure.
"We felt like we had control for parts of the game. Just some really silly personal errors and going away from our plan under pressure — at this level that's just not good enough.
"The frustrating part is that these things do take time, and we're working as hard as we can to show that."
Performing in the clutch has become a burgeoning issue for the Ferns recently, having won just one game decided by five goals or less under Southby. Additionally, they have blown four fourth-quarter leads, compared with earning two fourth-quarter comeback victories.
While those statistics have plenty of variables (to blow a fourth-quarter lead, you have to be good enough to be in front to begin with), Southby believes there is an underlying issue which needs fixing.
"When you get under pressure your vision narrows, and it's about taking a breath and being confident in how you play the game. For some of those players, they've felt it, they know these things, and I'm sure they'll come out stronger for it," she said.
If things don't look up before the Commonwealth Games, Southby's record may come under closer scrutiny. Her 33 per cent tally of wins against Australia and England is the worst of any Silver Ferns coach since 1948 - though there are extenuating circumstances.
Her predecessor - Waimarama Taumaunu – won only 38 per cent of those games, and Southby has been asked to take control of an inexperienced team which lacks the full depth of previous squads.
To get things back on the right track and avoid a record-equalling sixth straight defeat, the Ferns need to beat South Africa on Friday — a team they haven't lost to since 1995.
But South Africa lost to Australia by only four goals in their opener, and by seven in their most recent meeting with New Zealand. Despite holding a 29-1 all-time record against South Africa, Southby knows they are no longer easy beats.
"We know that we've got to be better than this [against South Africa]; I think it's been a really good wake-up call."
With the Games looming, those improvements need to start now.
NZ coaches vs Australia and England
Lois Muir 35 wins, 9 losses, 4 ties — 73 per cent
Lyn Gunson 16 wins, 8 losses — 67 per cent
Ruth Aitken 40 wins, 21 losses — 66 per cent
Yvonne Willering 11 wins, 10 losses — 52 per cent
Taini Jamison 2 wins, 2 losses — 50 per cent
Leigh Gibbs 5 wins, 7 losses — 42 per cent
Dixie Cockerton 2 wins, 3 losses — 40 per cent
Waimarama Taumaunu 14 wins, 17 losses — 38 per cent
Janine Southby 6 wins, 12 losses — 33 per cent
Myrtle Muir 0 wins, 4 losses — 0 per cent