England fought back in the second half to overcome an impressive Canada side in Vancouver and retain their WXV1 title.
The victory extends the Red Roses' winning run to 20 games, but the match proved to be their toughest test since their last defeat - in the World Cup final by New Zealand in 2022.
Canada, who would also have clinched the WXV1 title with a win, spent a large portion of the first half in England's 22, but could only manage one early try through scrum-half Justine Pelletier.
Prop Maud Muir quickly responded for the world number ones, but it proved to be a rare low-scoring start for John Mitchell's side.
Captain Alex Tessier got the amateur side back ahead with an excellent team try, before scores from replacement prop Sarah Bern and lock Zoe Aldcroft meant England retained the WXV1 title they won in Auckland last year.
Aldcroft's try came in the final play of the game and left Kevin Rouet's Canada rueing numerous missed opportunities as their six-game winning run came to an end and they fell to a first loss of 2024.
"I think we won ugly - sometimes you have to do that," Mitchell said.
"That was a proper Test match and that is great for us, so we will take a lot of good from this.
"This tournament was everything we wanted and needed, we have got to keep learning and getting better."
Canada back up World Cup claim
WXV1 hosts Canada, ranked second in the world, have stepped up in 2024 to emerge as the possible leading contenders to challenge England at next year's World Cup.
In front of a much improved crowd of 5,000 fans at BC Place, Canada started with a sense of urgency, turning down shots at goal to go in search of a try.
Comfortable wins over Ireland and France had ensured their shot at the title, and the muted celebrations when Pelletier slipped through Hannah Botterman's attempted tackle to grab the opening try showed nothing less than a statement victory was the plan.
A powerful carry off the back of the scrum from England number eight Alex Matthews helped set up Muir to barge her way over to quickly respond in an action-packed opening 10 minutes.
The Red Roses had started slowly before racking up the tries in convincing WXV1 wins over New Zealand and the United States, but were matched throughout the first half by their opponents.
Rather than assert their dominance, England's unforced errors opened the door for Canada, who failed to capitalise on their territorial superiority, with wing Paige Farries held up over the line by Holly Aitchison at the end of a competitive half.
Red Roses learn to finish strong
With full-back Ellie Kildunne in the sin-bin for deliberately slowing the ball down, England were punished when Tessier raced clear to finish off a free-flowing move that started in her side's own half and put the hosts 12-7 up.
As soon as Kildunne returned, wing Bo Westcombe-Evans was shown a yellow card for a deliberate slap down, but a number of handling errors from Canada meant they were unable to again take advantage of the extra player.
England's most recent defeat came against the Black Ferns in the 2022 World Cup showpiece, which ended the Red Roses' record 30-Test winning streak.
Having failed to close out that title decider when it mattered most, the Red Roses are unbeaten since - and showed steel to eke out the victory in Vancouver.
Mitchell turned to his bench - which he has nicknamed 'the super eight' - to seal the win against Canada and Bern delivered, with flanker Morwenna Talling also impressing after coming on for captain Marlie Packer.
"The super eight that came on gave us momentum, energy and front-foot ball, which is exactly what we asked from them at half-time," Packer added.
"It worked for us and we got the result we wanted."
Canada defeated New Zealand to win the Pacific Four Series earlier this year, but their inexperience showed in the closing stages as they continued to drop or kick the ball away at vital moments.
However, their performance indicates a rerun of the 2014 World Cup final - the last time England became world champions - could be on the cards next year.
The three-tier tournament was created to offer consistent annual international fixtures outside of World Cup years.
Each WXV tier consists of six countries who have qualified via continental tournaments and play-offs:
WXV1 in Canada featured the three sides from the 2024 Women's Six Nations - England, France and Ireland - plus the top three from the Pacific Four Series - Canada, New Zealand and the United States.
WXV2 in South Africa contained the remaining Six Nations sides - Scotland, Wales and Italy - as well as South Africa, Australia and Japan.
WXV3 in Dubai was made up of Spain, Madagascar, Fiji, Hong Kong, Netherlands and Samoa.
With each tier split into two pools, teams play the three sides in the other pool, with final placings determined by a points table.
Four points are awarded for a win and two for a draw, with the potential to pick up bonus points for scoring four tries or losing by seven points or fewer.
