Serbia's seemingly unstoppable World No. 1, Novak Djokovic, came into the Tokyo Games a heavy favorite in men's singles. He crushed his third round match against Spain's Alejandro Davidovich Fokina, winning 6-3, 6-1. 

Shortly after, Djokovic and Nina Stojanovic defeated Brazil's Luisa Stefani and Marcelo Melo 6-3, 6-4 in the first round of mixed doubles. 

Rio 2016 singles bronze medalist Kei Nishikori escaped an 82-minute (!) first set to secure a straight sets, third round win against Belarus' Ilya Ivashka, 7-6 (7), 6-0. Nishikori is the host nation's last hope for a singles medal following Naomi Osaka's dramatic third round departure. The former U.S. Open finalist is now ranked World No. 57, but he has seen something of a career resurgence the last few months. Unfortunately, he's scheduled to face Djokovic in the singles quarterfinals -- and a loss would prevent him from earning a medal. 

Japan also has a mixed doubles team in Ena Shibahara/Ben McLachlan, who beat the Kazakhstani team of Yaroslava Shvedova/Andrey Golubev in the first round of mixed doubles.  

Team USA still holds out hope for a medal in men's doubles. 

Austin Krajicek and Tennys Sandgren defeated Germany's Jan-Lennard Struff and Alexander Zverev 6-3, 7-6 in a men's doubles quarterfinal and will now face the top-seeded team of Nikola Mektic and Mate Pavic in the semifinals. 

Elsewhere, Bethanie Mattek-Sands and Jessica Pegula fell to Laura Pigossi and Luisa Stefani in a women's doubles quarterfinal.

Shortly after, Mattek-Sands and Rajeev Ram teamed up for mixed doubles, falling to Germany's Laura Siegemund and Kevin Krawietz in Round 1. 

Meanwhile, Great Britain's two-time reigning gold medalist Andy Murray is now entirely out of the Tokyo Olympics. He lost his quarterfinals doubles match alongside compatriot Joe Salisbury, falling to Croatia's Marin Cilic/Ivan Dodig 4-6, 7-6, 10-7. Citing injury, Murray pulled out of the singles tournament earlier this week to keep his doubles hopes alive.

OTHER RESULTS:

Daniil Medvedev (ROC) def. Fabio Fognini (ITA), 6-2, 3-6, 6-2 - Men's Singles Third Round

Ugo Humbert (FRA) def. Stefanos Tsitsipas (GRE), 2-6, 7-6, 6-2 - Men's Singles Third Round

Belinda Bencic (SUI) def. Anastasia Pavlyuchenkova (ROC), 6-0, 3-6, 6-3 - Women's Singles Quarterfinal