Ok - Here's my moral dilemma:?

My friend (entirely platonic) invited me to his best friend's (Dan's) 50th birthday party. I had never met his best friend before, so when the guest of honor's father stood up and announced that he was going to give away a very nice men's diamond ring to whomever could guess a certain number (between 1-100), I figured that I had no business being in the contest. I figured out that the number was probably 61 - the year of Dan's birth, and I told my friend so. He replied, "Really? I was going to guess another number!" However, when it was his turn to guess a number, he stood up and said, "61", and he won the ring. When everyone came to congratulate him, he never once mentioned to them that I was the one who told him the number. My question is: To whom should the ring be given? Should he keep it, or should I? Please help - this is coming between what I had thought to be a very nice friendship.