1. It was the only Grand Slam tournament to be played on three different surfaces. Before the Open Era, the French Open was the only major tennis tournament not to be played on the grass courts. From 1975 to 1977, players competed on the slow courts at Forest Hills. The United States Tennis Association (USTA) National Tennis Center was opened in 1978, which would mark the first time that the US Open was being played on DecoTurf. This would be its permanent venue.
2. The US Open would be the only major tournament to use a tiebreak on the deciding set. Spectators might want a longer match, but the players would prefer to settle the score in minutes. Come to think of it, a fifth-set tiebreak would be more exciting. Las Vegas, anyone?
3. The US Open was the first Grand Slam tournament to award equal prize money to the men's singles and women's singles winners. It happened in 1973, when Aussies John Newcombe and Margaret Court received the trophy and $25,000. The members of the USTA were pioneers, as it took a few more decades before the Australian Open, the French Open, and Wimbledon followed suit. And tennis would be one of the few sports that give equal prize money to the men and women.
4. The 1975 US Open saw Manuel Orantes of Spain and Chris Evert of the US winning the men's singles and women's singles titles respectively. There was something else, though. This marked the first time that floodlights were used. Night matches were held for the first time. This innovation turned into one of the most exciting features about the US Open, as some matches would go past midnight. It could be a blast for the remaining fans. Those who saw Fabio Fognini upset Rafael Nadal in their third-round clash last year didn't notice the time. It was 1:30 AM.
5. In 2004, the USTA introduced the US Open Series. This would mean three things. Matches were televised. More spectators. And players had something to strive for. Points were awarded to players who reached the round of 16 or better in the warm-up tournaments. The ones who have the most points could get a bonus of one million dollars if they won the US Open. It could be one long summer, but Roger Federer, Rafael Nadal, Kim Clijsters, and Serena Williams did it.
6. For three decades, fans witnessed Super Saturday. This was the penultimate day of the US Open, when the women's singles final was sandwiched between the men's singles semifinals. Some might have wondered if this was worse than the fifth-set tiebreak, and their prayers may have been answered. Unpredictable weather prompted the USTA to end it on 2012. Rain and thunder moved the men's singles finals to Monday. Andy Murray won his first major singles title, so it may be a sign.
7. The 2015 US Open marked the first all-Italian finals in the women's singles. Flavia Pennetta defeated Roberta Vinci in straight sets, which was followed by her announcement of retiring at the end of the season. But fans haven't seen the last of her. It won't be the season-ending WTA Championships.
8. The USTA introduced the instant replay reviews of calls during the 2006 Open. This was decided after the quarterfinal match between Jennifer Capriati and Serena Williams during the 2004 US Open. There were many questionable calls against Williams, but it won't mean Indian Wells.
9. The US Open offers the biggest paycheck. Novak Djokovic and Flavia Pennetta collected $3.3. million after winning the singles titles last year.
10. The middle weekend coincides with Labor Day. But it won't be a rest day for players.