Going into this game on a 10-match winning streak in all competitions, it looked like being the same old story when Sam Kerr took her tally for the WSL campaign into double figures, as she powerfully headed home from a corner with only five minutes on the clock.

However, Brighton hit back almost instantly with a set-piece of their own, as Aileen Whelan beat Carly Telford with a header at the back post, and it was clear the wind and sleet was going to have a part to play in proceedings.

The Blues were the dominant side for the rest of the contest, albeit with only flashes of our best football on display, and we were desperately unlucky not to restore our lead when substitute Pernille Harder’s volley on the stretch came back off the post.

Moments later, it was clear this wasn’t going to be our day, as Megan Connolly scored direct from a corner to spark jubilant scenes among the visiting team.

Despite Emma Hayes’ side laying siege to the Brighton goal for the final 10 minutes, a series of valiant blocks denied us again and again, as the Seagulls held on.

When the full-time whistle blew, there were roars of celebration from the visitors, who had just caused one of the biggest shocks of the season so far. Our WSL-record unbeaten run of 33 matches had finally come to an end, over two years since our last defeat in the competition. It was also the first time we’d failed to win a league game at Kingsmeadow since March 2019, a run of 14 victories.

There will be no time to dwell on this disappointment, as we face one of our biggest games of the season on Wednesday night when Arsenal are the visitors to Kingsmeadow. Kick-off for that one is 7pm and it could have huge ramifications for this season’s title race.

The Blues made light work of West Ham United in our most recent outing, a mid-week Continental League Cup semi-final that we won 6-0, but that didn’t stop Hayes ringing the changes for our 13th WSL match of the campaign.

Telford, Hannah Blundell, Erin Cuthbert, Jessie Fleming, Guro Reiten and Kerr returned to the starting XI, replacing Ann-Katrin Berger, Maren Mjelde, Millie Bright, Ji So-Yun, Fran Kirby and Harder.

Telford was selected for the 75th game of her Chelsea career, five of which have come this season, and she lined up behind a back four of Blundell, Sophie Ingle, Magdalena Eriksson and Jonna Andersson. For Ingle, it was another game in which she has shown her versatility by dropping back from midfield into defence.

After lining up in a 4-3-3 in our last game, this time it was a midfield diamond, with Melanie Leupolz at the base, Fleming and Reiten either side and Cuthbert at the tip. Kerr and Bethany England led the line.

As well as an alteration to the team’s shape, we were also sporting a change of attire, as the name of N+1 Singer adorned the back of the players’ shorts. The leading investment bank recently joined the Chelsea family as our first-ever Women’s shorts partner and this was the first game of our three-year partnership.

In recent weeks the Blues have made a more than welcome habit of scoring early goals, and we did so again today, thanks to our leading scorer in the WSL this term. It was so simple for the Australian, as she rose highest to get on the end of Cuthbert’s pin-point corner to the back post, directing a header that bounced down off the crossbar and into the back of the net.

Striking first and early has been the catalyst for dominant displays during our current winning streak – and, indeed, one had been enough to see off Brighton on the south coast before Christmas – but on this occasion it was a different story as they hit back almost immediately. Just as with the opener, it came from a corner and there was nothing Telford could do to keep out a bullet header from Whelan.

There’s no doubt the driving wind and sleet had played a part in the frantic start to proceedings, but after the two goals the game started to follow a similar pattern to previous meetings between the sides, which have typically involved Brighton getting everyone behind the ball and the Blues looking to pick a way through.

Hope Powell is one of the game’s more experienced tacticians, though, and her side looked to be following the game-plan to the letter as we were largely reduced to shots from distance and threatening from set-pieces. There was momentary concern for the Brighton defence when they allowed England to turn on the edge of the box, but our No9 could only direct her left-footed effort straight at Walsh.

The closest we came to restoring our lead before half-time came from another dead-ball situation, which was headed towards goal by Ingle but cleared off the line by Connolly. In fairness, the keeper probably had it covered, but with such tricky conditions it was not one to take any chances with, and Brighton went in at the break with parity.

Although several players were warming up during the interval, neither manager made any changes, and Chelsea started strongly, continuing to apply pressure while Brighton stood firm. There were a couple of half chances that we didn’t quite make the most of and then huge shouts for a penalty when the ball bounced off England and appeared to hit a Brighton hand. Replays suggested it would have been extremely harsh on the visitors.

That proved to be England’s last involvement, as she made way along with Reiten and Fleming in a triple change that saw Ji, Kirby and Harder bolster our attacking options 10 minutes into the second half. Mjelde joined them soon after, replacing Blundell at right-back, but the Norwegian’s first two involvements were to try and make something of passes that were overhit and then played behind her – indicative of the frustrations of the whole team at a display that was short of our fluent best.

That frustration was etched across the faces of every player in blue at the end of our best attacking move of the half, when Andersson was played in down the left and she crossed for Harder to direct a volley past the keeper but agonisingly back off the post. With Kerr lurking to tap in the rebound, the ball went straight back into the arms of the keeper.

Was it just going to have to be chalked down as one of those days? Well, things were about to go from bad to worse. Brighton won a corner on a rare foray forward and they made the set-piece count when Connolly swung one in from the left and, perhaps aided by the swirling wind inside Kingsmeadow, Telford wasn’t able to get a strong enough hand to the ball and it ended up in the back of the net.

With 12 minutes remaining, it was clear this was going to be one-way traffic for the remainder of the game. Brighton were pinned back in their own territory and we remained patient in our quest to find the equaliser. A wonderful move involving Harder and Kirby ended with Ji smashing a shot that a Brighton defender managed to block with a desperate lunge. It was a similar story when Harder found half a yard of space just outside the six-yard box. Somehow a yellow shirt was always in the way. It was the story of the game.

Four minutes of added time was a welcome boost as the clock ticked past 90, but there was simply no way past this dogged Brighton rearguard, although Kerr very nearly forced a mistake from Walsh as a cross skidded through and the keeper was forced to parry it away. But the visitors stood firm and their celebrations at full-time showed just how much this victory meant to them.

Chelsea (4-diamond-2) Telford; Blundell (Mjelde 68), Ingle, Eriksson (c), Andersson; Leupolz; Cuthbert, Fleming (Kirby 56); Reiten (Ji 56); England (Harder 56), KerrUnused subs Musovic, Carter, SpenceScorer Kerr 5

Brighton (4-2-3-1) Walsh; Le Tissier, Kerkdijk, Koivisto, Williams; Simpkins (Bance 62), Connolly; Whelan, Kaagman, Brazil; Lee (Jarret 78)Unused subs Fiskerstrand, Roe, Bowman, Heroum, SymondsScorers Whelan 8, Connolly 78Booked Bance 90

Referee Christiana Hattersley