Beth Mead picked up the ball in midfield in the 70th minute, advanced towards the Brighton area as Fern Whelan backtracked and from 30 yards unleashed a brilliant shot that arrowed into the far corner of the net. Arsenal had established a three-goal lead and there could be no doubt now: after a seven-year gap, they would be champions once more. It was an irresistible goal, suitably celebrated, and a fitting way for the Gunners to seal a title for which they have appeared destined since they launched their campaign with an avalanche of goals and points, and nine successive wins.

They have won seven in a row now, with one more game to play. The visit of last season’s champions and this season’s closest challengers, Manchester City, for the final fixture in a fortnight, a match which might have engendered so much trepidation had they failed to secure a result here, can instead be an occasion of pure celebration. While a team who have lost only two league games all season have had to come to terms with the possibility of finishing second in the Premier League, a team who have not lost at all are doomed to failure in the WSL.

“Maybe the fans would have liked a grand final at Borehamwood, but I credit the players and the staff because we controlled our destiny,” said Joe Montemurro, the Arsenal manager. “We controlled games, we controlled whether we were going to win it or not going to win it, and that’s a beautiful place to be. These things don’t happen much in life but the way they did it, the way they went about it, was fantastic.”

This was Arsenal’s 19th league fixture, of which they have won 17. Monday will be the first anniversary of the last occasion they dropped points against a team other than City and Chelsea. “I think if I look at Arsenal, Manchester City and Chelsea, they’re on another level,” said Hope Powell, the Brighton manager. “Arsenal are a top-quality side. They play nice football, they’re accurate, they’re precise. In a sense I guess I’m pleased for them, they’re deserved champions.”

Vivianne Miedema has powered Arsenal towards the title with a season-long goal glut, and she again proved decisive here, scoring once and creating another before half-time. Brighton were resolute in the opening period, even if they offered little threat of their own, and with five midfielders dropping back to protect the back four they presented, at least for a while, a formidable barrier.

Miedema twice rendered them irrelevant, though, first by winning the ball from the tumbling Victoria Williams before powering a shot over Marie Hourihan and into the top of the net from 25 yards, and then by lifting a pass over the backline and into the path of Katie McCabe, who was left with a straightforward finish past an exposed goalkeeper.

In front of a WSL-record crowd of 5,265, the Gunners proceeded to take complete control. But for a brief spell at the start of the second half, when Siri van Veenendaal in the Arsenal goal was even forced to make an actual save, they bent this game to their will.

Once Mead further extended their lead Brighton might have been overwhelmed. Daniëlle van de Donk added a fourth, exchanging passes with Kim Little inside the area before being given far too much time to pick her spot. Ini Umotong might have won a penalty for the home side with six minutes to go, but by then this had become less a contest than a countdown to a celebration. With Brighton assisting with a champion-themed post-match playlist, when that moment came there was no holding back.

“I’ve been in tears on the pitch and I almost feel a bit silly, but I don’t think I should ever apologise for having that emotion about the club that I love,” said Leah Williamson, at Arsenal since the age of nine and celebrating her first league title at 22. “It’s all I’ve wanted to do since I joined this team. When I was a youth player coming up I was thinking, ‘I’m just going to wander into the Arsenal team and win trophies.’ It’s not that easy and the game’s come on so much so to win that out there, in a competitive league, is absolutely unbelievable. The fact it’s taken this long almost makes it sweeter. I’m almost out of emotion today.”