"It always pulls on the heartstrings to see a mate in pain like that - she was a Trojan tonight at the back there and with her playing so well it was a massive blow. But we have to pull together as a group," said Langman following the 47-34 loss - their eighth straight defeat to Australia.
This was supposed to be a night of celebration for Kopua, who became the Ferns most-capped skipper when she led her side out on court for the 63rd time in Sydney to break Lyn Gunson's long-standing record. The star defender was clearly fired up for the occasion, with one of her first touches coming from a stunning intercept. Despite her side being out of the match by halftime as they trailed the Diamonds 24-15, Kopua continued to throw herself at everything, coming up with some brilliant defensive plays to keep Australian shooter Caitlin Bassett quiet and limit the damage on the scoreboard.
But her milestone match came to a disastrous end minutes into the final spell, when she wrenched her knee awkwardly after tangling with Bassett. From the look of agony on Kopua's face as she was propped up by teammate Cathrine Latu, it was immediately clear she wouldn't be adding to her 63 tests any time soon.
If Kopua is found to have serious structural damage to her knee, it will likely rule her out of next year's World Cup, raising the question of whether she will return at all.
The sickening sight of Kopua - a well-respected player in Australia - being carried off the court in tears subdued the packed stadium in Sydney for the match, as the home side cruised to a comfortable win after dominating from start to finish.
Diamonds captain Laura Geitz said the sadness of seeing her Kiwi counterpart go down with injury tempered her excitement in notching up another series win.
"Everyone in the Diamonds has the utmost respect for that woman, she is nothing short of a champion and it is just absolutely devastating when you see a player like that who is the backbone of that team go down in such a horrible way," she said.
The win saw the Diamonds officially sew up the Constellation Cup for another year as they took an unassailable 3-0 lead in the series, although with 26-goals the difference in goal aggregate after the first two tests it already looked pretty safe in their trophy cabinet before last night.
The next time the Ferns return to Allphones Arena will be for next year's World Cup - an event the New Zealand side will be glancing ahead to with much trepidation given the Diamonds sustained period of dominance, and the potential they may be returning without their captain.
Constellation Cup - game 3
Allphones Arena, Sydney
Q1: 14-7
Q2: 24-15 (10-8)
Q3: 35-24 (11-9)
Q4: 47-34 (12-10)
Shooting stats:
New Zealand
Cathrine Latu 14/14
Ameliaranne Wells 7/8
Jodi Brown 8/12
Bailey Mes 5/9
Australia
Caitlin Bassett 32/37
Natalie Medhurst 10/10
Tegan Caldwell 5/6