England sealed a third consecutive Women's Six Nations title by edging France 10-6 in an absorbing game at Twickenham on Saturday.
Poppy Cleall charged over the try line in the final minute of the first half and Emily Scarratt added the extras to make amends for two earlier penalty misses.
France came out firing in the second half and reduced the gap to one point through the boot of Caroline Drouin as the error count of a nervy English side climbed.
But the Red Roses wrestled back the momentum in the closing stages and Scarratt's last-minute penalty sealed victory.
"It doesn't need to be big, flamboyant scorelines every week," Scarratt told the BBC.
"The defence was unreal and we had to dig in. I could have made it easier with a couple of penalties in the first half but I'm really proud of the effort. The desire to not let them over the tryline was superb."
The format of the competition was changed this year due to the COVID-19 pandemic, with England and France facing off in the final as the winners of two three-team groups, rather than the usual six-team round-robin format.
France travelled to London on the back of seven straight defeats to England, but three of those were by a margin of two points and another close encounter between the two heavyweights of European women's rugby soon unfolded.
Scarratt screamed in frustration after missing a penalty early on and the England captain skewed another simple kick wide five minutes later, before going off for 10 minutes as she passed a Head Injury Assessment.
France full-back Emilie Boulard's try was disallowed for a forward pass and Drouin pulled a penalty wide of the target.
The first points eventually arrived in the dying seconds of the half when Cleall, picked at No. 8 ahead of captain Sarah Hunter, bundled over the line from the base of a ruck, having started the move by charging out of a scrum towards the posts.
France came out strongly after the break and Drouin's penalty hit the post on the 43rd minute, but she slotted home her next attempt three minutes later.
Errors started to creep into the English performance but their ferocious defence held firm until Drouin's boot reduced the gap to one point with seven minutes remaining.
With the game on a knife edge, the hosts regained control and put the result beyond doubt with Scarratt's late penalty.
"It was a really tough, physical game and we knew it would come down to the wire. In terms of physical application both sides really put a great effort in," England head coach Simon Middleton said.
"Two teams put each under massive pressure, the breakdown was a complete fight and the physios will be really busy. It was a brutal affair."
Earlier, Ireland sealed third place with a 25-5 win over Italy in Dublin.