(London)  --  Novak Djokovic is tying two of men's tennis best with his 20th Grand Slam victory after claiming the Wimbledon title Sunday.  Djokovic defeated Italy's Matteo Berrettini in four sets to tie Roger Federer and Rafael Nadal in Grand Slam wins.  It is his third Grand Slam title this year, having already won the Australian and French opens.  The last time a men's tennis player arrived at the U.S. Open with victories in the other three major championships was 1969 when Rod Laver did it.