Everton claimed their first Women's Super League win of the season after a controversial penalty saw the Toffees beat Liverpool 1-0 at Goodison Park.
The Blues were the beneficiaries of a decision from referee Abigail Byrne, who pointed to the spot after Fuka Nagano's dangling leg tripped Honoka Hayashi. Despite the challenge happening outside the box, a penalty was given and was neatly tucked away by Katja Snoeijs.
Liverpool manager Matt Beard expressed his frustration at the "disappointing" decision that "cost" his side.
"Ultimately a referee's decision has cost us potentially three points," he told Sky Sports. "Everton are a tough side when they get in front and when they gift them an opportunity like that…there's no unobstructed view. The referee's got a great view.
"There's four of them there that can help each other make the decisions and nine times out of 10, you ask the fourth official and the mind's already made up. I don't know what to say anymore. It happens week in, week out, not just for us."
Referee Byrne also dismissed three Liverpool penalty shouts, with Olivia Smith going down after contact with Clare Wheeler before Sara Holmgaard collided with Ceri Holland in the box. A third appeal came late on with Holmgaard involved again in a coming together with Cornelia Kapocs. Beard feels his side should have been given a decision as a result.
"I feel the challenge on Ceri Holland and Olivia Smith in the box warranted penalties for us," he said. "My players left nothing on that pitch today and they 100 per cent deserve something out of the game."
Liverpool started strong but allowed their rivals into the game by not taking advantage of their early spells in the ascendancy. Instead, Everton used their home advantage to swing the momentum of the derby in their favour.
Goalkeeper Courtney Brosnan was the star of the show for the Toffees as they earned a clean sheet. A double save after the break to keep out Nagano before a point-blank stop later in the second half ensured Brian Sorensen's side could keep all three points.
The loss for Liverpool represents their first defeat on their travels, ending a run of eight on the road without a loss going back to January. The defeat also means Beard's side have now gone five without a win and are six points behind Manchester United in the table.
Victory for Sorensen's side moves them up from the bottom of the table into ninth place.
Ebony Salmon scored a 94th-minute stunner to earn Aston Villa their first Women's Super League win of the season with a dramatic 3-2 victory over Crystal Palace.
Salmon, a second-half substitute, turned on the edge of the box before smashing the ball into the roof of the net to the relief of manager Robert de Pauw.
Palace had equalised in only the 86th minute when Annabel Blanchard volleyed in from Ashleigh Weerden's cross to earn what looked like a point.
The visitors had punished Villa for being typically wasteful in the first half by taking the lead through My Cato just after the half-hour mark.
However, Villa hit back quickly with an equaliser, Anna Patten slotting home from inside the box before Rachel Daly fired them ahead in the fifth minute of added time - but that was nothing compared to the late drama of the second half.
Manchester United returned to winning ways with a comfortable 2-0 victory over Leicester at the King Power Stadium to stay unbeaten in the WSL.
Marc Skinner's side had endured a difficult few weeks heading into this game, having drawn three on the bounce after winning their opening four games in the league.
But goals from Elisabeth Terland and Celine Bizet ensure United head into their next league game at leaders Chelsea, the only other unbeaten team in the WSL, just a point away from third-placed Brighton and the Champions League places with a game in hand.
Terland headed in the opener in first-half stoppage-time before Bizet slotted home her first United goals since moving from Tottenham with nine minutes to spare.
Leicester now sit third from bottom, ahead of bottom-side Crystal Palace only on goal difference, after suffering a fifth defeat of the season just eight games in.