Some things never change

OK, so I was out at the pub (or, rather, an array of pubs) with friends from work last night. At one point, we ran into a bunch of other people from work, one of whom was with a group of other friends.

And one of those other friends was someone I knew from my school days. Oh horror, I was about to be outed as a complete nerd in front of the people to whom I had been trying to project an image of normality.

Actually, that turned out not to be a problem - I think I managed to bluff my way through, with much manly handshaking and very little cowering in horror.

But then the guy from my work did something I honestly hadn't expected. "You know, Lifewish, that girl over there [one of the others from work] fancies you. Hey, Sarah*, come over here!"

How very schoolyard.

The problem, though, is that, while I may have been exposed to this particular method of putting someone on the spot whilst I was in secondary school, I'm still not sure how to deal with it. I think I handled it at the time by glaring at the guy and turning to talk to someone else, but that just shows that he managed to get to me - a sign of weakness. It also leaves poor Sarah in the lurch somewhat.

I could have gone the other way, and played along. However, I'm honestly not sure I know the rules for that game well enough. And again that merely validates Andy's approach and leaves Sarah with the bill (metaphorically speaking).

I could have tried to turn the tables, for example by getting to Sarah first and telling her loudly that Andy was calling her over to say how much he fancied her. That's getting warmer in its probable effect on Andy, but means I'm actively contributing to the winding up of Sarah.

What I really need if I'm to achieve Quality in this area is a simple approach that will:
1) cut Andy off before he can mess Sarah about
2) leave Andy looking foolish
3) not require me to be an asshole

Any thoughts?

(Disclaimer: neither Andy nor I was remotely sober at the time, so it's always possible I've misunderstood him or his motivation - albeit IMO not likely. Regardless, it's still an interesting question.)

* Name changed to protect the probably innocent - it's highly unlikely that she does in fact fancy me, and even less likely that she'd tell Andy** about it. Actually it's infinitely more probable that she fancies Andy, the company heartthrob, which makes the whole debacle even nastier.

** The guilty deserve no protection. However, there are half a dozen Andys at my work, including some lovely chaps, so anyone who knows my secret identity should not draw conclusions.