You need at 4 players in the same league as you. Set it up as a one game playoff. Once everyone is in, you have to play at one game against each player in the league. You can quit out when there is less the 14 minutes remaining on the clock and the other person will get the win. Once everyone has played three games, you'll have the top 2 players in the playoffs. This game you have to complete, so just have one player score a goal and run out the clock. You'll get this achievement and 'It's the playoffs' at the end of the match. Swap players until everyone has won a playoff game.