Applying for a Masters in Statistics but scored poorly on one course, explain is SOP?

Hi all, I am keen in applying for MSc Statistics but I have done poorly for one very relevant/important course as I fell sick on the day of my exams. I am worried that this is going to look poorly on my proficiency in the subject.

Now the grade I got for this module is going to stick out like a sore thumb in my transcript. Should I explain that I was sick on the day of the exam on my statement of purpose / personal statement, or should I not mention about it at all?

Better if you can to ask one of your referee's to mention it.

I agree, better to have the ref explain the anomaly rather than use up your wordcount.