I drank a 750ml bottle of wine 64 hours ago. What are my chances of passing an ETG urine test?

When is your ETG test? If it is in the next few days you will more than likely test positive - but this depends on the test and how sensitive it is.

Apparently you could test positive up to 80 - 120 hours after you last consumed alcohol.

My advice would be to try to sweat it out. Drink plenty of water and do as much exercise as you can, in that way you may be able to pass more of the alcohol through your skin but be sure to replace the fluids lost by drinking plenty of water.

Hopefully, if you have not had much to drink before this, you may get through, but I thought it  important to tell you that there is a chance of a positive result. Forewarned is forearmed and hopefully you can do something (such as exercise) to raise your chances of a negative result.

Good luck, I really do hope it goes well for you.