My friend and his fiance' wanted to introduce me to a HB they thought I may like so they invited me to her christmas party. We chatted a bit and built some rapport but didn't get a chance to connect too much
since I didn't want to interrupt her hosting. She was going to join us at the bar we went too after the party but ended up staying home to clean up. My buddy apparently talked to her, before
leaving the party and she mentioned she thought i was cute but didn't get enough of a chance to talk to me. My friend said he would work on setting it up or getting me her number so perhaps we can go on a date sometime. ONly issue is he's gone to San Fran for work the next two months only coming back on the weekends.

Coincidentally a ran into her and my friend's fiancee on the street the next day. We made small talk and as they had their tennis rackets in hand I mentioned I love playing tennis. The girl
responded that we'll have to play sometime (IOI); unfortunately i didn't catch on and missed a great opportunity to number close.

I found the girl on facebook, question is should I play it cool and wait for my friend to set something up or to be invited by them to an event that she's at too or should i be proactive and facebook chat her.
Background i'm 29 she's 25 and apparently she just got out of a LTR back in November. I don't want to seem to invested or eager and it could be creepy looking her up on FB but on the other hand I feel like a PUA should be going after a target.

Thoughts on best way of # closing?

Do not FB stalk her at this point. You're right, you missed the perfect opp to # close her when she said "we will have to play tennis sometime". O well. Lay back brother. If you hit her up on fb she will probably run.
YES. OR, covertly have your guy friend set up a sitch where you and her will be in the same place. You said he's back on the weekends. Plenty of opps there to link up with her. Stay in the background until then. You hitting her up on FB will look way too fucking hungry. And when you meet up with her, play it like you have plenty of options even if you don't, in a non arrogant manner.