Chelsea Ladies opened their 2017 Spring Series campaign with an emphatic 6-0 win over newly promoted Yeovil, while Arsenal's season began with a goalless draw at Sunderland.
Yeovil held out until half-time but South Korea's Ji So-Yun netted twice in first-half stoppage time for 2015 double winners Chelsea.
Drew Spence, Erin Cuthbert, Crystal Dunn and Ramona Bachmann made it six.
Meanwhile, part-time Sunderland's draw was their second from two games so far.
The Lady Black Cats held out against in-form Birmingham last Sunday and similarly frustrated the Gunners at the Hetton Centre, as goalkeeper Anke Preuss produced late saves from Arsenal's Danielle van de Donk and Chloe Kelly.
- Match stats: Chelsea Ladies 6-0 Yeovil Town Ladies
- Match stats: Sunderland Ladies 0-0 Arsenal Ladies
- Saturday's report: Man City knocked out of Europe
- Friday's report: Liverpool Ladies 4-2 Reading Women
Blues hit ground running in WSL 1
Goals were far easier to come by for Emma Hayes' Chelsea, who had 23 shots on target and a further 23 off target against a Yeovil side who won promotion with the second-tier title last season.
Hayes saw second-half goals from three of her pre-season signings, as 18-year-old Scotland midfielder Cuthbert, United States winger Dunn and Switzerland star Bachmann all opened their Women's Super League One accounts.
Chelsea are bidding for league success in the Spring Series after disappointment in the Women's FA Cup, where they were knocked out in the semi-finals on penalties by Birmingham.
Last year's WSL 1 champions, Manchester City, are yet to start their Spring Series season owing to fixture clashes with their maiden Women's Champions League campaign, which ended on Saturday despite a 1-0 win in Lyon in the second leg of their last-four tie.
Having played two games already, Liverpool are the early WSL 1 leaders after beating Reading on Friday to make it two wins from two.