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Competing at the hard-court ATP Masters 1000 for the first time since 2021, Nishikori overcame physical struggles to down a fired-up Jaume Munar 6-2, 5-7, 7-6(3) and earn a second-round spot. The former World No. 4 called for the physio for a leg injury midway through the third set and within two games was also struggling with cramp, but he nonetheless held firm for a two-hour, 57-minute victory.

“It was not easy. I almost gave up because I was struggling with my body,” said Nishikori. “In the third set I was cramping pretty badly, but somehow I came back and won, so a very good match.”

Nishikori has battled back from long-term injury to reestablish himself in the Top 100 of the PIF ATP Rankings, and in January he reached his first ATP Tour final for six years in Hong Kong. Currently the World No. 76, he seemed set for a routine victory in his maiden Lexus ATP Head2Head meeting with Munar after making a fast start, but the match became complicated after he let slip a 4-3 lead with a break in the second set.

“I knew I was playing well from the beginning, and he took the chance in the second set, but even then, I was still happy with my tennis,” reflected Nishikori. “I just tried to stay focused and I think he had more chances in the third set, but I tried to compete and fight until the end.”

After saving 10 of 14 break points he faced against Munaur in Indian Wells. Nishikori set a second-round meeting with 18th seed Ugo Humbert.

In other early Day 1 action in the California desert, wild card Tristan Boyer enjoyed a dream Masters 1000 main-draw debut by securing a 4-6, 6-2, 7-6(4) victory against Australia's Aleksandar Vukic. Boyer, whose only previous match in Indian Wells was a first-round qualifying encounter as a 16-year-old seven years ago, will next take on his countryman and 10th seed Tommy Paul.

American qualifier Colton Smith, making his ATP Tour debut, rallied past World No. 40 Flavio Cobolli 3-6, 6-2, 6-2. A senior at the University of Arizona, Smith will next play 31st seed Alex Michelsen.

China’s Bu yunchaokete spoiled American Nishesh Basavareddy’s homecoming with a 7-5, 6-4 victory. The 23-year-old won 27/33 (82 per cent) of his first-serve points, according to Infosys ATP Stats, to set a second-round showdown with fifth seed Daniil Medvedev.

Thiago Seyboth Wild and Christopher O’Connell each notched three-set triumphs to kick-start their BNP Paribas Open campaigns. Seyboth Wild saved two match points in the deciding set before prevailing 4-6, 7-5, 7-6(6) against Alexandre Muller.

O’Connell won a topsy-turvy duel with Roberto Carballes Baena 6-3, 0-6, 6-1. In the second round, Seyboth Wild will take on last week’s Dubai champion Stefanos Tsitsipas, while O’Connell plays Matteo Berrettini.

Tallon Griekspoor overcame Delray Beach champion Miomir Kecmanovic 6-7(5), 6-4, 6-3 in two hours, 15 minutes.

 Fabian Marozsan ousted Pedro Martinez 6-3, 6-2.