Which yacht won the first Americas Cup race?

That could almost be a trick question. The first race, put on by the Brits in 1851, wasn't called the America's Cup. However, it was won by a boat called America, and subsequent races for that trophy became known as the America's Cup race. The winner of the next race, the first race known as the America's Cup race, was a boat named Magic. So, the answer to your question could be either America or Magic depending on which you consider to be the first America's Cup race.