World number one Novak Djokovic reached the Australian Open quarter-finals for the first time since 2016 with a hard-fought win over Daniil Medvedev.
The 31-year-old Serb earned a 6-4 6-7 (5-7) 6-2 6-3 victory over the 15th seed in Melbourne.
Djokovic was not at his fluent best, but outlasted Medvedev to win in three hours and 15 minutes.
Russia's Medvedev, 22, grew frustrated as he paid the price for only taking two of nine break points.
Medvedev's resistance continued until the end, saving two match points before Djokovic took the third with a wonderful cross-court winner.