Answer

Even if it did become defective, that would only mean that the blessings were not recited over wine, or were recited over wine that was not in perfect condition. They are still the Seven Blessings, and it makes no practical difference whether the cup became defective or not, except perhaps that ideally, after he drank, he should have switched to another cup.
But logically it does not seem to me that it became defective, since he drank only after the blessing over the wine, and the other blessings are ancillary to the blessing over the wine. It is not reasonable that drinking after the blessing over benefit would render the cup defective with respect to the remaining blessings. It would render it defective for other blessings, or for Kiddush on the Sabbath afterward.