In front of 4790 people, a record figure for a WSL game not played at a men’s stadium, the Norwegian slotted home her second-half spot-kick after sub Fran Kirby had been fouled. The result keeps us top of the WSL table and maintains our sparkling recent form.

It was a tight contest in Surrey with clear chances few and far between, but when the big moments came we delivered. After Mjelde’s cool penalty, Ann Katrin-Berger produced a world-class save to deny Ella Toone and preserve our lead. It was as good a piece of goalkeeping as you will see.

Ramona Bachmann and Ji So-Yun had both come close for us in the first half, while the visitors’ biggest threat stemmed from Lauren James, Reece’s little sister.

The introduction of Kirby off the bench on the hour added some extra thrust to our attacking play, and it was the no.14 who was brought down soon after for the match’s decisive incident. The win is our seventh in a row in all competitions and was thoroughly enjoyed by those of a Chelsea persuasion inside a sold-out Kingsmeadow.

Our last league outing was three weeks ago, the hard-fought comeback win over West Ham, and Emma Hayes saw no reason to change her line-up from that success in east London. There was a great sight on the bench as Hannah Blundell returned after a lengthy lay-off.

As well as being managed by Casey Stoney, Manchester United’s team, also unchanged, contained a couple of familiar faces. Jackie Groenen spent 18 months at Chelsea earlier in the decade, while James is the younger sister of Reece, one of the emerging stars of our men’s team.

At a packed-out Kingsmeadow, we soon got in to our stride. A couple of neat interchanges down the left created space for crosses that were cleared, the second leading to a corner which caused problems before Magdalena Eriksson blazed over.

The skipper had to be at her best down the other end shortly afterwards, blocking a dangerous Leah Gulton attempt from Groenen’s cutback. The Dutch attacker wanted a pass from Kirsty Hanson as the Red Devils kept the pressure up, but the striker went it alone after pinching possession off Jonna Andersson. We were grateful to see her effort from a tight angle crash into the side-netting.

Man United have made a promising start to their maiden campaign at this level, and it was quickly apparent why, with James in particular a threat leading the line. Chelsea supporters know exactly what Groenen is capable of, meanwhile, and on 20 minutes she spun on the edge of the box and fired straight at Berger.

Midway through the opening half our best attack yet resulted in our first meaningful effort. Millie Bright won possession and fed Ji. The South Korean glided goalwards and picked out Bachmann, who created space for a shot which Mary Earps palmed behind. From the corner, Bright leaped highest but couldn’t generate sufficient power on her header to beat Earps.

Our keeper Berger then took a blow to the head from James as she raced out to collect a through-ball. After a lengthy delay the German was okay to continue.

Play restarted and a smooth Chelsea move ended with Ji stepping inside but shooting wide, Mjelde having done plenty of the hard work with an overlapping run and cross that Earps couldn’t hold.

The Norwegian showed her value defensively with a vital interception after James had beaten two Blues for pace. As we broke from the resulting corner, it needed a couple of visiting players to illegally stop the speedy Guro Reiten in her tracks.

The teams headed in level after a well-contested half of football that was just missing the finishing touch.

The Blues took a while to get going when play got underway again, but out of nothing almost took the lead on the hour. Erin Cuthbert latched on to a ball over the top, finally finding space behind the visitors’ rearguard. She opted to try and half-volley her striker past Earps but the ball whistled beyond the far post, too.

Hayes then made her first sub, bringing Kirby on for Reiten. The striker had been presented with a shirt marking her century of Chelsea appearances before kick-off, and she immediately made an impact today. Slipped into the inside channel, her best hope looked like winning a corner but Millie Turner crunched through the back of her. The referee had no hesitation in pointing to the spot.

Mjelde stepped up and found the bottom left-hand corner despite Earps’ best efforts. Twenty-five minutes remained.

For a spell Chelsea deemed attack to be the best form of defence as we sought to hold on to our lead. Staying on the front foot helped keep the visitors away from our box, and down the other end we continued to threaten, with Kirby helping pull the strings and Beth England twice having shots blocked.

Drew Spence for Bachmann was our second sub and with 10 minutes to go she slipped in Kirby, who tried to take it round Earps but was eventually crowded out as the keeper got a hand to the ball.

We were almost immediately punished for that miss, as two United subs combined. Jess Sigsworth's deflected cross reached an unmarked Toone, whose first-time volley looked destined for the top corner. Berger had other ideas, however, brilliantly tipping the ball on to the underside of the bar. It hit her back on the way down and bounced agonisingly close to the line before Bright hooked to safety. The save proved a matchwinning one.

We survived the final stages, which included a couple of United corners Berger dealt with admirably, to pick up a crucial three points on another landmark day for Chelsea Women.

Today was a sell-out at Kingsmeadow and to make sure you see us take on Tottenham in the Continental Cup on Wednesday night, buy tickets now

Chelsea (4-3-3) Berger; Mjelde, Bright, Eriksson (c), Andersson; Cuthbert, Ingle, Ji (Carter 87); Bachmann (Spence 79), England, Reiten (Kirby 63).Unused subs Telford, Blundell, Cooper.Scorer Mjelde (pen) 65Booked Cuthbert 45+2

Manchester United Earps, A.Turner, McManus, M.Turner, Harris, Ladd, Zelem (c) (Toone 74), Groenen, Hanson, James (Ross 80), Galton (Sigsworth 55).Unused subs Mikalsen, Okvist, Arnot, Smith.Booked A.Turner 12, McManus 42

Referee Jack PackmanCrowd 4790