I think it’s not unusual for football commentators to refer to the midfielder as being the heart of a team. Playing in the center of the field, distributing the ball to others, etc. So on that basis I thought it worked and was quite clever.

Here’s a sample from a Google search (footballtalentspotters.com): “The heart of any football team, central midfield is probably the most physically-demanding, intelligence-requiring role on the field, requiring both the greatest variation of attributes and the fiercest ball-winning drive.”

But, sorry, ‘heart of a pitch’ just doesn’t work for me – but then I’m no football fan [not that shaped ball, anyway]. It just seems to me there must be a much better clue for ‘heart of hearts’.

5d Well, a ‘midfielder’ does mainly play in the middle, or ‘heart’, of the pitch so I thought this was OK.

Thanks for the blog, especially the explanation of EMBARGO: I just didn’t associate ‘ego’ with ‘one’.

Apart from that and taking far too long to get 11ac, there was no great challenge here, though I did think some of the clues were rather odd. I agree with your doubts about ‘obscured by’ in 15ac: ‘confused with’ would have served better – and surely candelabra are more than ‘a set of ornaments’?

13ac: OR for ‘other ranks’ is commonplace – but R by itself?

9dn: ‘heart’ = ‘midfielder’?

I’ve come across Lorca [and orc!] several times in crosswords – and I don’t think zabaglione is particularly exotic!

I did like 22 and 26ac.