The Grand Slam is a tennis tournament, while the ATP is an orginization. (Association of Tennis Professionals.)
If we are talking about tennis, The Australian Open is organised by Tennis Australia. It is sanctioned by the world governing body as an official tournament by the ITF (International Tennis Federation) and included in the ATP (Association of Tennis Professionals) World Tour.
A Grand Slam is a tournament of the ranked players and it spans across different continents. There are 4 Grand Slams in a year. The ATP is the Association of Tennis Professionals.
Milos raonic of canada
Pat Rafter
ATP: Association Of Tennis Professionals
Association of Tennis Professionals
ATP refers to the Association of Tennis Players. The ATP World Tour is the circuit in which professional male tennis players play. It is like the NBA or NFL of tennis.
ATP Tour Championship Tennis happened in 1994.
ATP Tour Championship Tennis was created in 1994.
ATP
Technically the ATP season ends some time after the U.S. Open so it is the last Grand Slam Tournament played, but in the next season the Australian Open is the next Grand Slam tournament played after the US Open.