England passed their Le Crunch test with flying colours, running in six tries for a 42-21 victory against 14-player France after Assia Khalfaoui's second-half red card.
Packer, who started the Championship by winning her 100th cap against Italy, heaped praise on her side after their sixth successive Guinness Women’s Six Nations title.
"I’m super proud of all the girls,” she said. "We have been building as a group on and off the pitch. We are well and truly into a John Mitchell era - we will keep growing as a group.
"What an amazing atmosphere and quite hostile, but it means we can turn it up when we need to.
"It means everything, but I am lifting it with the girls I am not on my own.
"It has taken a squad effort not just as coaches and players, but from the backroom staff as well."
England didn't have it all their own way in Bordeaux and were under the pump for much of the second half.
Khalfaoui’s dismissal for head contact on Morwenna Talling seemed to rouse the hosts, who scored the first points of the second half courtesy of Marine Ménager.
But Alex Matthews’ second try made victory safe and ensured there would be no late drama.
Matthews said: "In the second half we were uncomfortable. We lost our connection, but to still pull together and get the win is brilliant.
"One of our values is our bond so those moments off the pitch bring us closer, it helps to get results like that!"
It was a particularly special triumph for scrum-half Natasha 'Mo' Hunt. After being left out of the 2022 World Cup squad, she played just 68 minutes in England’s 2023 Six Nations campaign.
But she has been an integral member of the squad this time, starting four of England’s five matches, thriving alongside halfback partner Holly Aitchison.
“So much has happened and this group means so much to me,” said Hunt.
“My journey has been spoken about a lot so to own it and do it with this girl [Aitchison] is incredible.
“We knew and we talked in the week about being in an arm-wrestle. For us, it was about wrestling momentum back and the girls were unreal and stuck in the fight. I couldn't be prouder."