Liverpool pulled off a shock 1-0 win at Arsenal in front of a record Women's Super League crowd.
There were 54,115 fans at the Emirates Stadium for the season opener, which was settled by a goal from Miri Taylor early in the second half.
Taylor slotted in a cross from Missy Bo Kearns in the 48th minute to stun the Gunners home support.
The Reds held off plenty of Arsenal pressure but Jonas Eidevall's side, who were knocked out of the Champions League qualifiers last month, could not find a way back into the match.
Champions Chelsea opened their WSL title defence with a 2-1 win over Tottenham at Stamford Bridge.
Chelsea debutant Mia Fishel headed the home side into a 27th-minute lead. England international Lauren James added another early in the second half, though Spurs set up a tense closing 15 minutes when Martha Thomas pulled a goal back.
Manchester United came from behind to beat Aston Villa 2-1 with a stoppage-time goal from substitute Rachel Williams at Villa Park, where the hosts saw Kirsty Hanson sent off.
Villa took the lead through England international Rachel Daly, only for Lucia Garcia to quickly have United back on level terms.
Just when it seemed both teams would have to settle for a point, Williams headed in Nikita Parris' deflected cross to secure United a dramatic victory.
Manchester City won 2-0 at West Ham as Jill Roord scored on her debut. Lauren Hemp broke the deadlock early in the second half with a curling effort before Chloe Kelly then saw her penalty saved.
Netherlands international Roord, a club-record summer signing from Wolfsburg, slotted in to open her City account in the 55th minute.
Leicester came from behind to beat newly-promoted Bristol City 4-2 at Ashton Gate. While Elisabeth TerlandRead on irishexaminer.com