Novak Djokovic admitted that his rivalry with Rafael Nadal is something that helps keep him competitive as he aims to level the Slam race.As he heads into his tenth Australian Open semi-finals on Friday, Djokovic is just two wins away from a 22nd Grand Slam title which would put him level with Nadal’s all-time record.The 35-year-old admitted that the rivalry is something which keeps him motivated to carry on winning the big events.‘’It does keep me going, of course,” Djokovic told the tournament’s official website.“I’m trying to balance things out between the professional goals that I have and it’s always high school for me, you know, trying to reach another title.“I have had plenty of success in Australia, so that obviously fee …