The world No. 1 from Serbia defied the heat—and perhaps even good sense—by signing up to play mixed doubles as well as singles for his country.

UCLA alone has four alums representing their respective countries later this month.

The 23-year-old American kicked off his Miami Open campaign Friday, winning eight of 11 net points during his 6-2, 6-2 win over countryman Marcos Giron.

Giron impressed in his victory over his friend Tommy Paul, but can he take out another one of his buddies in Taylor Fritz?

Opening Wednesday's action on Grandstand, Danielle Collins had no problem advancing past Kristina Mladenovic, 6-3, 6-3. Later, Marcos Giron won an all-American battle over Tommy Paul, 7-6 (5), 6-4.

On Wednesday, Svetlana Kuznetsova and Alizé Cornet will clash at the Miami Open, where they have made a combined 28 appearances. Tommy Paul and Marcos Giron will also meet in an all-American showdown.

Fourth-seeded Andrey Rublev eased past American Marcos Giron, 7-6 (1), 6-3, after 79 minutes, while countryman Karen Khachanov upstaged 2015 champion Stan Wawrinka, 6-4, 7-5, on Tuesday at the ABN AMRO World Tennis Tournament.

Players—including Victoria Azarenka, Kei Nishikori, Sloane Stephens and Angelique Kerber—who entered Australia on flights QR7493 from Los Angeles and EY8004 from Abu Dhabi, will be forced to self-isolate for 14 days after PCR results from passengers.

“It has been a hell of a year. The year before I went from 300 in the world to right near 100 and had a good run at Indian Wells, which was awesome," the 27-year-old American says