When was the first tennis major comprising the Grand Slam before the US Open first held?
Australian Open The Australian Open is a major tennis tournament held annually over the last fortnight of January in Melbourne, Australia. First held in 1905, the tournament is chronologically the first of the four Grand Slam tennis events of the year – the other three being the French Open, Wimbledon and the US Open. It features men's and women's singles; men's, women's and mixed doubles and junior's championships; as well as wheelchair, legends and exhibition events. Prior to 1988 the tournament had been played on grass courts, but since then two types of hardcourt surfaces have been used at Melbourne Park – green coloured Rebound Ace up to 2007 and, afterwards, blue Plexicushion.
1991 ATP Tour The 1991 IBM ATP Tour was the elite tour for professional men's tennis organized by the ATP Tour. The IBM ATP Tour included the Grand Slam tournaments (organized by the International Tennis Federation (ITF)), the ATP Championship Series, Single-Week, the ATP Championship Series, the ATP World Series and the ATP Tour World Championships. The World Team Cup, Davis Cup (organized by the ITF) and Grand Slam Cup (organized by the ITF) are included in this calendar but did not count towards the Tour.