3 to 1 means that 1 wins 3. 3 for 1 means that 1 wins 2.So "2 and 1" means that the winner was 2 holes ahead with 1 hole to play (the match ended after No. 17), "3 and 2" means 3 holes ahead to with 2 holes to play (the match ended after No. 16), and so on.
