This was a meeting between the top and bottom sides in the WSL, but the home side put in a performance that belied their lowly position in the standings as they frustrated us for much of a wet evening in the Midlands.

That being said, it could have been a far more comfortable game had we made the most of two wonderful openings in the first five minutes, when Harder fired a gilt-edged chance wide of the target and Sam Kerr, the recently crowned FWA Women’s Player of the Year, smashed a shot against the underside of the bar.

We struggled to create many chances of note after that, and it looked like it just might have been one of those nights until the 70th minute when the referee pointed to the penalty spot for a Birmingham City handball after Niamh Charles headed a cross from Jonna Andersson towards goal.

The pressure was on Harder as she stepped up from 12 yards, but the end result was never in doubt as she confidently rolled her spot-kick into the bottom right corner to send Birmingham keeper Emily Ramsey the wrong way.

The Dane roared in celebration, aware of just how important that goal could be in deciding the destination of this season’s WSL title. More than 300 Blues fans had made the trip to the Midlands among a crowd just shy of 1,500, and finally they had their reward.

With one game to go, our destiny remains in our own hands and Manchester United are the visitors to a sold-out Kingsmeadow next Sunday, when we know a victory will clinch a third straight title. It could be all over by then if Arsenal are beaten in the north-London derby on Wednesday night, but whatever happens this has been another thrilling race to be crowned WSL champions.

Ahead of the game Hayes spoke about the importance of the whole squad and for this Sunday evening trip to the Midlands she made use of three players who didn’t start against Tottenham Hotspur on Thursday. Ann-Katrin Berger, back from suspension, Charles and Jessie Fleming were those to come into the line-up in place of Zecira Musovic, Andersson and Erin Cuthbert.

It was a back three comprising Millie Bright, Jess Carter and Magdalena Eriksson in front of Berger, while Sophie Ingle, on her 150th appearance for the Blues, was once again the midfield shield who allowed the quartet of Charles, Harder, Fleming and Guro Reiten plenty of attacking freedom. Our two goalscorers on Thursday, Bethany England and Kerr, continued their strike partnership.

The importance of the first goal would not have been lost on either manager, particularly with Birmingham’s game plan to sit deep and frustrate, and twice inside the opening five minutes we could have gone in front.

First, Bright’s quick free-kick caught Birmingham napping and Ingle sent Harder through with a clear sight of goal. The Dane steadied herself and struck a firm effort across Ramsey but it crept just wide of the far post. Two minutes later we went even closer through Kerr, who had scored hat-tricks in her last two matches against Birmingham. Reiten’s cutback found her in acres of space on the edge of the box and the Blues No20 smashed a left-footed shot that cannoned against the underside of the crossbar and away to safety.

If we thought those early chances would be a sign of things to come, our fellow Blues clearly had other ideas, as they stuck diligently to their defensive duties and left us with very little space in which to work. There was the occasional moment of joy, such as when Reiten was found with a yard of space to work in down the left, but the Norwegian, who has been in great goalscoring form of late, was caught in two minds and her effort drifted harmlessly wide.

All that action came inside the first 15 minutes, and for the rest of the half we struggled to make inroads against the WSL’s bottom side. Other than a daisy cutter from Bright from miles out and a Fleming header at the back stick that just missed the target, there was little of note to report in the attacking third. At the other end, Birmingham were posing a threat from set-plays and although they weren’t able to call Berger into meaningful action, it was clear they were the happier side at the break.

Hayes opted to make a change at the interval as she sent on Cuthbert in place of England and the Scot had the chance to make an immediate impact when the ball fell to her on the edge of the box, but the bounce made it a little awkward and her effort sailed over the bar.

By this point the heavens had opened at St Andrew’s, typically for a bank-holiday weekend, which meant the ball was holding up in the surface, but we were causing problems in the air and Eriksson was nearly the beneficiary of a rush of blood from Ramsey, who came charging out for a cross but was beaten by the Swede’s flick-on. Unfortunately, there was no one in a position to take advantage and the Birmingham keeper could breathe a huge sigh of relief.

The skipper had our next chance on the hour mark, staying up for the second phase of a set-piece and striking powerfully at goal but straight into the face of Louise Quinn, who wears the armband for Birmingham. It looked destined for the back of the net, but still our wait for a goal went on.

Two more substitutions were thrown on by Hayes, as Lauren James and Andersson replaced Ingle and Carter, and two chances followed in quick succession. Harder was denied by a brilliant save from Ramsey and then Kerr pulled a shot wide when well placed in the area.

The changes had made a big difference, with the overloads down the flanks resulting in plenty of space for crosses, and one such situation gave us our clearest chance yet to open the scoring. Andersson had so much time to whip in a wonderful ball that her opposite full-back Charles headed towards goal, only for Robertson’s outstretched arm to divert it away from danger. The referee had no hesitation in pointing to the spot.

Harder was the player for the big moment, stepping up from 12 yards with so much at stake. You’d have been hard pressed to tell that was the case, though, as the Dane coolly rolled the ball into the bottom right corner, sending Ramsey the wrong way, and all of the frustration of the previous 70 minutes came roaring out in her celebration.

From then on, it was all about game management and making sure we saw out another crucial victory. On came Drew Spence and Maren Mjelde, in place of the goalscorer and Kerr, and the former was soon screaming for a penalty after she was crudely taken out inside the penalty area. This time, however, the referee waved away the protests.

That came just before four minutes of stoppage time was indicated, and there was one nervy moment when Berger had to make a stunning fingertip save to deny substitute Whelan an equaliser. But that was about as tense as it got, and we saw out yet another victory in our relentless charge towards the WSL title.

This one hadn’t been our prettiest win – as Cuthbert put it in her post-match interview, they don’t put any photos on the title – but it mattered not a jot. Three points leaves us knowing exactly what we have to do on the final day of the campaign, should the title race go that far. All eyes will be on the north-London derby that takes place on Wednesday night before then.

Next up for the Blues is Manchester United at Kingsmeadow next Sunday. Tickets for that one have sold out, but it’s not your last chance to see us in action this term as we face Manchester City a week later in the Women’s FA Cup final. Click here to buy your ticket for that one now!

Birmingham City (3-5-2) Ramsey; Scott, Louise Quinn (c), Lawley; Cowie (Whipp 67), Finn, Murray, Robertson (Whelan 86), Sarri; Pennock (Smith 67), Lucy QuinnUnused subs Hourihan, Jenner, Wildgoose, Worsey, Ryan-Doyle, EwensBooked Cowie 35, Robertson 43, Scott 90+5

Chelsea (3-1-4-2) Berger; Bright, Carter (Andersson 64), Eriksson (c); Ingle (James 64); Charles, Harder (Spence 82), Fleming, Reiten; England (Cuthbert h/t), Kerr (Mjelde 86)Unused subs Musovic, Nouwen, AbdullinaScorer Harder (pen) 71Booked Berger 90+4

Referee Emily Heaslip

Attendance 1,429