(Photo credit: David Gonzales-Imagn Images)

World No. 1 Carlos Alcaraz weathered a rain delay and an injury scare to defeat Argentina's Sebastian Baez 6-4, 6-2 in the first round of the Japan Open on Thursday in Tokyo.

The top-seeded Spaniard stumbled to the court in the first set, clutching his left leg. After having his heel and ankle taped during a medical timeout, he powered through to the second round. Up next is Belgium's Zizou Bergs, who rallied to beat Chengdu champion Alejandro Tabilo of Chile 1-6, 7-6 (2), 7-6 (4).

No. 2 seed Taylor Fritz came from behind for a 4-6, 6-3, 7-6 (3) win over Canadian Gabriel Diallo. No. 3 Holger Rune of Denmark defeated Serbia's Hamad Medjedovic 7-6 (7), 6-1. No. 4 Casper Ruud of Norway rallied to beat Japan's Shintaro Mochizuki 4-6, 6-1, 6-1. Two seeded players fell, with Japanese qualifier Sho Shimabukuro ousting No. 5 Czech Tomas Machac 6-3, 7-6 (4) and Jenson Brooksby taking down No. 6 Ugo Humbert of France 7-6 (4), 6-3.

China Open

Top-seeded Jannik Sinner of Italy swept past two-time Beijing finalist Marin Cilic of Croatia 6-2, 6-2 in 82 minutes to advance to the second round.

The 2023 champion here, Sinner saved the only break point he faced and looked sharp in his first appearance since his U.S. Open final loss to Carlos Alcaraz. Up next is Frenchman Terence Atmane, a 6-4, 6-2 winner against Chinese wild card Zhizhen Zhang.

Atmane's countryman, Alexandre Muller, notched a 4-6, 7-6 (5), 6-4 upset of fifth-seeded Russian Karen Khachanov. In other first-round action, Spain's Alejandro Davidovich Fokina crushed Argentina's Camilo Ugo Carabelli 6-1, 6-3 and Hungary's Fabian Marozsan eliminated France's Benjamin Bonzi 7-6 (1), 6-3.

--Field Level Media