Your question is a fact pattern with a lot of variables. It is always consent until someone alleges it is not consent is probably the easiest answer.
I do not know if this will be helpful to you, but I recently found this webpage that does an excellent job of summarizing various sexual assault and consent laws in Illinois: http://www.northwestern.edu/womenscenter/issues-information/sexual-assault/defining-sexual-assault.html
I hope this helps answer your questions. Good luck.
This answer is marginal legal advice and does not constitute an attorney-client relationship. Every client and case is unique. The best advice is to always consult with an attorney. Free legal resources at www.ZippToCourt.com
If this is a bar bet, go elsewhere.
If this happened to you, and she is telling you there was no consent. Get to a criminal attorney, unless she is blackmailing you, in which case go to the police.
If you found this Answer to be helpful, please mark it as such. Remember, however, free advice is worth every penny you paid for it. This is only generalized commentary on your question. It is not to be taken as legal advice. I am a lawyer – but not your lawyer! Even "in person" interviews leave attorneys with plenty of questions – the Internet makes it crazy! Thank you Chuck Watson 217.544.6165
I agree with most of the posts above, however, I add the following comment.
If a person realizes at some point during a situation, as briefly described by you, that the other party is intoxicated, or induced by other means, that realization may be used as the prerequisite intent of a non-consensual sexual encounter by the prosecution. It would be against advice of most counsel to speak of any impressions that were formed by the accused party. It is best that the person makes no statements to the authorities and contacts a criminal attorney immediately.
If the "victim" of this situation believes that they were unable to consent because of their level of intoxication then they will need to show more then just the fact that they were intoxicated after a "few" drinks.
Voluntary intoxication by either, or both, parties does not lead to much of a defense/offense.