It was a day of shocks in the Barclays FA Women's Super League with Reading denting Manchester United's title challenge with a 2-0 win.
But that was nothing compared to what happened at Kingsmeadow where Albion ended leaders Chelsea's 33-match unbeaten run thanks to goals from Aileen Whelan, on her 50th appearance, and Megan Connolly who scored direct from a corner to seal a 2-1 win.
While most of the attention on Sunday focused on Manchester City's 2-1 win at Arsenal, the media gave Albion's triumph – their first in seven games – plenty of coverage.
The BBC Sport website felt it would be business as usual when Sam Kerr gave Chelsea an early lead.
“A home victory, a 19th successive win in all competitions, looked likely following Kerr's goal from Erin Cuthbert's set-piece - the Australian's 10th in 13 games this season. But a side who had lost eight of their 14 league games this term replied through a similarly imposing header from Whelan - just Brighton's 10th goal this season.
Brighton sat deep but pressed aggressively as soon as the Blues crossed the halfway line - a tactic that disrupted the home side's fluency. A frustrated and vocal Blues boss Emma Hayes made a triple change just over 10 minutes into the second half, Jo So-Yun adding much-needed creativity in midfield and Fran Kirby and Pernille Harder - with 19 goals between them - injecting greater pace and movement.
“But despite strong, persistent pressure chances remained at a premium, and Connolly snatched an improbable win on a rare Brighton attack when stand-in keeper Carly Telford made a mess of a near-post corner with 12 minutes left, to leave Hayes frustrated.
"Our intensity and our aggression was really poor. You have to take the game to the opponent, and you have to work for spaces and chances and I don't think we did that well at all. We've given away two set-piece goals which I don't think we've done in my whole time here. They had three shots on target and scored two goals. That's extremely poor from us."
Another manager surprised by the result was Manchester City's Gareth Taylor, who was asked about it by The Guardian's Suzanne Wrack after City improved their title hopes against the Gunners.
“Chelsea dominated at Kingsmeadow, with 77% possession against Hope Powell’s Brighton. Emma Hayes' team had 30 shots to Brighton's three but two of the visitors' shots resulted in goals,” wrote Wrack.
“People will be looking at those two results and say they are a shock, they are a surprise, but this is football. That is why we love it – it happens. Fortunately for us, it hasn't happened to us,” said Taylor.
In The Sun, Isabelle Barker wrote that the WSL title race has been blown open spectacularly after Brighton inflicted Chelsea's first league defeat in over two years.
"Sam Kerr gave the champs an early lead after nodding home on five minutes, after she was left unmarked at the far post at Kingsmeadow.
"But just three minutes later Aileen Whelan got the Seagulls back in it after rising highest to head in Megan Connolly’s inch-perfect corner. Bethany England rattled the crossbar from 12 yards before the break, and Sophie Ingle saw a header cleared off the line - but Chelsea couldn't find a breakthrough.
"Against the run of play, Blues stopper Carly Telford shirked her duties and palmed Megan Connolly's corner into her own net to make it 2-1 with ten minutes left to play."