2021 gave Novak Djokovic a myriad of satisfactions, but also some bitter disappointments. Number 2 ATP came close to the ‘Calendar Grand Slam’ last year, having to surrender to Daniil Medvedev in the final act of the US Open.After winning his first three Majors of the season, the Serbian star has paid dearly for his exhaustion and tension at Arthur Ashe Stadium. Had he also prevailed in New York, the 34-year-old from Belgrade would have become the second man in the Open Era after Rod Laver to win all four Grand Slams in the same year.Some insiders have criticized Nole’s choice to play the Tokyo Olympics, which deprived him of the energy needed to complete the job in the Big Apple. His dream of winning gold for Serbia was shattered in the semifinals against Ale …