Following last week's controversial draw against Real Madrid, victory was a necessity at Stamford Bridge. It was duly delivered by Hayes's side, although not in swaggering style. Grit and resolve were required.

Kerr put Chelsea ahead on the half-hour mark after excellent work from Lauren James, but the visitors went into the interval level after Thea Greboval headed home from a corner.

Fran Kirby was introduced at half time; it proved an important change from Hayes. By 60 minutes, Chelsea held a 3-1 advantage and Kerr had completed her hat-trick. Gloss was then put on the result in stoppage time as Sophie Ingle, another substitute, netted.

Reflecting on Chelsea's performance, Hayes said: 'I think the accumulation of games caught up a little bit with us tonight. I don’t think people really realise how hard it is to keep doing it.

'I thought it was a performance where we dug something out – and the strength came from the bench tonight.

'Sophie coming on [in the second half], I thought she brought the calm, composed impact we needed. Same with Maren (Mjelde) and Eve Perisset, Mia (Fishel) getting her first Champions League appearance.

'Some days, you’ve got to dig it out and need the bench. Today, the bench did their job.’

The hat-trick scored by Kerr was that of a pure goalscorer. Her first was a smart finish from close range; her second an example of intelligent movement; her third born from ingenuity and technique.

And, as Kerr herself highlighted ahead of the game, she is still not quite yet 100 pre cent fit following a disrupted pre-season due to injury.

'If that is her at 80 per cent – or whatever the per cent she is – then I’ll take that every week, that is not bad. I can’t wait for the 100 per cent version to come,' Hayes said with a smile.

‘I said to Paul (Green) in the dressing room before the game, she doesn’t get credit for all the other little bits she does and while she’s not, by her standards, top top yet, I don’t know anyone who puts the ball away like she does.

'She is so alert, so decisive with her movement. She can make a bad pass a good pass and I think the third goal, the lob, is just brilliant centre forward play.’