under one's skin

[phxj]

Dear Sir/Ms

What is the meaning of 'under one's skin'?, as showed in the quotation as the following:When Federer got embroiled in a long chat with Romano Grillotti, the umpire, at 3-3 in the second set, Safin was getting under the world No 1’s skin.

Thanks

phxj

[Casiopea]

The idiom to get under one's skin means, to irritate. I have no idea, though, how it fits in to the context you provided. Sorry.