Novak Djokovic made amends for his doubles exit at the Japan Open by progressing to the second round of the singles on Tuesday.
The top-ranked Serb - attempting to win a title on his tournament debut for the 10th time - beat Australian Alexei Popyrin 6-4, 6-2 and next faces local wild card entry Go Soeda.
Holding to love in four of his nine service games, Djokovic did not give any break-point opportunities to Popyrin in the match.
Djokovic, alongside Filip Krajinovic, had been knocked out of the doubles by the fourth-seeded Mate Pavic and Bruno Soares on Monday. That was Djokovic's first competitive match since retiring during his fourth-round clash with Stan Wawrinka at the U.S. Open.
Japanese wild card Taro Daniel caused the biggest upset of the day by beating second-seeded Borna Coric 6-4, 4-6, 7-6 (5) after a grueling 2 hours, 39 minutes in 30-degree C (86 F) heat on the Colosseum show court.
Daniel is joined in the second round by compatriot Yasutaka Uchiyama, the qualifier needing only 54 minutes to dismantle fourth-seeded Benoit Paire 6-2, 6-2. He next meets Radu Albot, who beat Krajinovic 6-3, 7-5.
Uchiyama's victory means four of the five Japanese main draw entries made it through to the second round.
Reilly Opelka won an all-American duel with seventh-seeded Taylor Fritz, 6-3, 6-4, to set up a second-round match against Frenchman Gilles Simon, who beat Pablo Andujar 6-4, 6-0.
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