Chelsea Ladies became Women's Super League 1 champions for the first time and completed a domestic double by beating Sunderland.
Emma Hayes's side added the league title to the FA Cup they won in August.
England striker Fran Kirby netted twice after Ji So-Yun's opener, before Gemma Davison's late fourth.
Chelsea avoided a repeat of final-day drama in 2014, when they narrowly lost out on goal difference to Liverpool, as they denied Manchester City the title.
The Blues, who began the final round of fixtures with a two-point cushion over City, knew a win would be enough to secure top spot.
They took the lead when Eniola Aluko beat Sunderland right-back Abby Holmes with a burst of pace down the left and squared for South Korea international Ji, who calmly found the bottom corner via the post.
Aluko almost made it two before the break, but her long-range effort whistled just wide of the far upright, after Kirby had gone close when one-on-one.
After half-time, Davison beat her marker before crossing for Kirby to tap into an empty net, before the former Reading striker made it three with a sweet, left-footed strike from outside the box.
Davison's low finish made the scoreline comfortable, emphasising the quality of Chelsea's outstanding front four of Aluko, Ji, Kirby and Davison.
Sunderland, who were guaranteed to finish their first season in WSL 1 in fourth place before Sunday, extended their winless run in all competitions to eight games.
Chelsea Ladies manager Emma Hayes: "Tonight was a champions performance, full of character. We looked like champions tonight.
"That front four, when they get around the outside of teams and play very good football, they're capable of beating any team in Europe.
"After the FA Cup final, we have had the confidence of being a winning team. Since the FA Cup final, we've been on a different level."
Chelsea Ladies: Lindahl (Hourihan), Blundell, Flaherty, Fahey, Davison, Aluko, Ji (Coombs), Rafferty, Kirby, Chapman, Spence (Bright).
Subs not used: Borges, Brett, Meiwald, Ayane.
Sunderland Ladies: Olsen, Holmes (Potts), Greenwell, Furness, Bannon, Ramshaw (Etherington), McDougall, Mead, Joice, Kelly (Roche), Williams.
Subs not used: Harkness, Hill, Beer, Potts, Brown.
Referee: Adrian Quelch.