IrishPride - your problem is that you did not burn off the alcohol in the wine. Most recipes fail to mention this step, but believe me, in commercial kitchens this is the first step in a wine-based marinade. Basically, you do this:
Take your wine, broth or other liquid and bring it to a boil. Let it boil for 3-5 minutes if you are using alcohol. Turn off the heat, add your aromatics (spices, peppercorns, herbs, lemon slices, garlic onion or whatever), cover the pot and let it cool to room temperature. THEN
you pour it into a Ziploc bag with the duck breasts and you're golden! Put the bag in a bowl or tupperware and squoosh it around every now and again to make sure all the marinade gets onto the meat.
When you get ready to cook, take the meat out of the marinade and dry it well
before cooking. This is important - otherwise you will not get a good sear.
Personally, I would not marinate for more than 2 days.
Hope this helps.
I have lots of other duck recipes here,
if you are interested. Good Luck!
I love all of God's creatures, properly prepared.