New York - Former US Open runner-up Kei Nishikori admitted he would have liked longer on court after Argentine qualifier Marco Trungelliti quit with injury just 47 minutes into Monday's first-round encounter.
Seventh seed Nishikori raced into a 6-1, 4-1 lead before world number 205 Trungelliti was forced to retire due to a back problem.
"It's a little bit sad to see. He's a great player," a consoling Nishikori said of his stricken opponent.
"For me I played great tennis from the beginning and I'm happy with the way I played today."
"But honestly I wanted to play a little more because I was feeling good on the court and I wanted to get little more confidence, playing more points, more confidence playing matches. I think my rhythm was going," he added.
Nishikori has enjoyed his best Grand Slam results in New York, losing the 2014 final to Marin Cilic, while reaching the last four on his two most recent appearances, in 2016 and 2018.
"First set I was playing really well, and he started feeling pain after first set. Of course that's going to help me for the physical side. I'm really fresh now."
The Japanese star, who faces 108th-ranked American Bradley Klahn in the next round, has reached the quarter-finals or better at the last five majors.
Nishikori is one of several players looking to end the dominance of Novak Djokovic, Rafael Nadal and Roger Federer, the trio accounting for each of the past 11 Grand Slam titles.
"I hope I can be the one to beat top three, but I feel like those three guys are still different level," said Nishikori, who suffered early defeats at both Montreal and Cincinnati this month.
"But maybe including me... you see (Dominic) Thiem playing final, even though last year Thiem played a great match against Rafa here, and I think a couple of guys are getting closer.
"Of course Sascha (Zverev) is a great player and couple young guys, you know, Felix (Auger-Aliassime), (Denis) Shapovalov, (Nick) Kyrgios, those couple guys who are coming up, too.
"I think in maybe a few years I'm sure it's going to change a little bit," he continued.
"I hope I can sneak in there and win the title sometimes. For me, yeah, that's going to be my big goal to win a Masters or Grand Slams."
US Open results on Monday (x denotes seeding):
Novak Djokovic (SRB x1) bt Roberto Carballes Baena (ESP) 6-4, 6-1, 6-4
Denis Kudla (USA) bt Janko Tipsarevic (SRB) 3-6, 6-1, 7-6 (7/5), 6-1
Dusan Lajovic (SRB x27) bt Steve Darcis (BEL) 7-5, 6-3, 6-3
Jenson Brooksby (USA) bt Tomas Berdych (CZE) 6-1, 2-6, 6-4, 6-4
Nikoloz Basilashvili (GEO x17) bt Marton Fucsovics (HUN) 3-6, 6-4, 6-2, 3-6, 6-3
Daniil Medvedev (RUS x5) bt Prajnesh Gunneswaran (IND) 6-4, 6-1, 6-2
Dan Evans (GBR) bt Adrian Mannarino (FRA) 6-4, 6-3, 2-6, 6-3
Cristian Garin (CHI x31) bt Christopher Eubanks (USA) 3-6, 7-6 (7/5), 6-4, 6-7 (4/7), 6-3
Alex de Minaur (AUS) bt Pierre-Hugues Herbert (FRA) 6-4, 6-2, 6-7 (6/8), 7-5
Bradley Klahn (USA) bt Thiago Monteiro (BRA) 6-3, 6-2, 6-3
Kei Nishikori (JPN x7) bt Marco Trungelliti (ARG) 6-1, 4-1 retired
Venus Williams (USA) bt Zheng Saisai (CHN) 6-1, 6-0
Rebecca Peterson (SWE) bt Monica Puig (PUR) 6-3, 6-3
Dayana Yastremska (UKR x32) bt Monica Niculescu (ROM) 6-4, 1-6, 6-2
Johanna Konta (GBR x16) bt Daria Kasatkina (RUS) 6-1, 4-6, 6-2
Margarita Gasparyan (RUS) bt Priscilla Hon (AUS) 7-6 (7/4), 6-4
Ekaterina Alexandrova (RUS) bt Samantha Stosur (AUS) 6-1, 6-3
Ons Jabeur (TUN) bt Caroline Garcia (FRA x27) 7-6 (10/8), 6-2
Aliaksandra Sasnovich (BLR) bt Jennifer Brady (USA) 6-1, 4-6, 6-0
Mariam Bolkvadze (GEO) bt Bernarda Pera (USA) 6-3, 5-7, 6-4
Karolina Pliskova (CZE x3) bt Tereza Martincova (CZE) 7-6 (8/6), 7-6 (7/3)
Hsieh Su-Wei (TPE x29) bt Jana Cepelova (SVK) 6-4, 5-7, 6-3
Petra Martic (CRO x22) bt Tamara Zidansek (SLO) 6-4, 4-6, 6-1
Ana Bogdan (ROM) bt Harriet Dart (GBR) 6-3, 6-1
Iga Swiatek (POL) bt Ivana Jorovic (SRB) 6-0, 6-1
Anastasija Sevastova (LAT x12) bt Eugenie Bouchard (CAN) 6-3, 6-3
Kristina Mladenovic (FRA) bt Angelique Kerber (GER x14) 7-5, 0-6, 6-4
Fiona Ferro (FRA) bt Daria Gavrilova (AUS) 6-3, 6-4
Alison Van Uytvanck (BEL) bt Viktoria Kuzmova (SVK) 6-4, 6-4
Lauren Davis (USA) bt Johanna Larsson (SWE) 7-5, 6-2
Ashleigh Barty (AUS x2) bt Zarina Diyas (KAZ) 1-6, 6-3, 6-2