England suffered a 58-46 loss to Australia and missed out on their first ever Quad Series trophy.
The Roses, who held a one-goal lead before the period, conceded 18 goals in 15 minutes, with England coach Jess Thirlby saying "we ran out of steam."
"That last quarter wasn't good enough - we lost our structures, we were found wanting defensively," she added.
Australia, who came into this tournament as an unknown outfit, claimed their sixth Quad Series title.
The two sides had played out a tight draw in Tuesday's match.Everything you need to know about the Quad SeriesFind out how you can get into netball
A fast start saw the Diamonds get to an early three-goal lead while England tried to settle and, although they had no trouble in winning the ball back, they struggled to convert defence to attack and shift the ball through the mid-court to the shooters.
Similar to Tuesday's match, where England were not at their best but managed to earn a draw in the last seconds of the game, the Roses took the opening quarter to bed in.
But Eleanor Cardwell, who demonstrated her shooting prowess against the Diamonds on Tuesday, stood strong in the circle, forcing the Aussie's head coach Stacey Marinkovich to bring on Sarah Klau at goal keeper and move Courtney Bruce to goal defence.
Thirlby, who looked calm on the sideline, didn't make a change until the third quarter, which perhaps indicates where her intentions lie ahead of the Commonwealth Games selection.
The Roses held a two-goal cushion heading into the half-time break and, after a tight third quarter, a remarkable defensive effort from England saw Geva Mentor claim possession and prevent Australia drawing level at the end of the period.
With 15 minutes left on the board to make history and the prospect of extra time looming, England fell four goals behind. Impact substitution George Fisher, who has shot so well through this series, missed her first shot, allowing the Diamonds to take the turnover and a six-goal lead.
Australia suddenly looked comfortable while England missed shots and struggled to find that something special they desperately needed.
The final quarter saw England score a miserable five goals to Australia's 18 as the Diamonds achieved their biggest victory over the Roses since 2016.
Australia had come into this series as a bit of an unknown, having played just four international matches in two years, but showed that they can never be written off. Paige Hadley and Gretel Bueta, who had a baby last year and returned to win player of the series put in stand-out performances.
Earlier, New Zealand beat South Africa 51-50 in a tight match which saw the world champions finish third in the series.
'There will be bigger stages where we need to be at our best'
It was the first time the two coaches had met since taking up their respective positions, and Thirlby has often talked about 'having a seat at the table' when it comes to the powerhouses of netball in Australia and New Zealand.
This series has shown there is no doubt England are among the elite, but Thirlby said you have to show "resilience and robustness" to compete with the best in the world.
"It's going to hurt - losing a game of that nature," she said. "We gave it a really good go but I don't think the last 15 minutes should define how well we have done.
"We were 15 minutes too short but it gives us the hunger for next time we meet, and we have got finals netball under our belts. We've learnt a lot over this Quad Series.
As Thirlby's players head off to their respective domestic leagues she will take time to reflect and assess who will make the final cut for the Commonwealth Games.
"They need to be afforded the chance to shine there too before any decisions are made. There will be bigger stages where we need to be at our best."
Quarter-time scoresQ1 - 14-12Q2 - 27-25Q3 - 41-40Q4 - 46-58
England: GK - Mentor; GD - Guscoth; WD - Cobden; C - Guthrie; WA - Metcalf; GA - Housby; GS - Cardwell
Australia: GK - Bruce; GD - Weston; WD - Brazill; C - Hadley; WA - Watson; GA - Wood; GS - Bueta