MELBOURNE, Australia (AP) — It took about a week for Novak Djokovic to go from worrying about whether he simply could play a match at all on his injured left hamstring to thinking he can win the Australian Open. And one pain-free, nearly perfect performance in the fourth round Monday made a world of difference. “Tonight, the way I played, the way I felt, gives me reason now to believe that I can go all the way,” Djokovic said after completely overwhelming 22nd-seeded Alex de Minaur 6-2, 6-1, 6-2 to reach the quarterfinals for the 13th time at Melbourne Park and 54th time at all Grand Slam tournaments.