Novak remains on course for the Golden Slam after winning his QF match in Tokyo.
Top seed Novak Djokovic dropped just two games in Tokyo quarter-finals as he continued his quest for a first Olympic tennis gold medal.
The 34-year-old Serbian star beat Kei Nishikori of Japan 6-2, 6-0 in just 70 minutes.
Djokovic converted five of his 10 break point chances and saved the only break point he faced during the 19th career meeting between the two (17-2 H2H record).
“Matches are not getting easier, but my level of tennis is getting better and better,” Novak said. “I know that I’m kind of a player that the further the tournament goes, the better I’m feeling on the court. That’s the case here. It was my best performance of the tournament tonight against a very good opponent. I know Kei’s game very well. Him playing in Japan, this court where he had lots of success. I knew that he was going to play very quick, and he was not going to give me a lot of time, so I had to be very alert. I feel I had an answer for everything he had.”
Match statistics: aces (3-0), double faults (4-2), winners (8-6), unforced errors (13-16), total points won (59-31).
Novak goes on to play no.4 seed Alexander Zverev on Saturday. The German dispatched Jeremy Chardy (FRA) in straight sets.
Pablo Carreno Busta (ESP) and Karen Khachanov (ROC) complete semi-final line-up.
In the mixed doubles quarter-finals, Novak and Nina Stojanovic produced a dominant display to defeat Germans Kevin Krawietz and Laura Siegemund 6-1, 6-2. They will next face Aslan Karatsev and Elena Vesnina of Russia.