Top-ranked defending champion Novak Djokovic cruised into the second round while French Open champion Ashleigh Barty and third seed Karolina Pliskova struggled but advanced.

Serbian star Djokovic, who has won four of the past five Grand Slam singles titles, dispatched Spain’s 76th-ranked Roberto Carballes Baena 6-4, 6-1, 6-4.

“Getting out of the blocks, it takes time for you to feel comfortable on the court,” Djokovic said. “I’m quite pleased with my performance and looking forward to the next one.”

Djokovic, trying to become the first back-to-back US Open winner since Federer won from 2004-2008, will next face Argentina’s 56th-ranked Juan Ignacio Londero.

Former US Open runner-up Kei Nishikori of Japan raced into the second round in just 47 minutes on Monday after Argentine qualifier Marco Trungelliti quit with injury.

Serbia’s Dusan Lajovic also joined Nishikori after his victory against Steve Darcis of Belgium. Seventh seed Nishikori led 6-1, 4-1 when world No 205 Trungelliti was forced to retire due to a back problem.

Nishikori will meet American Bradley Klahn in the next round. The Japanese star, a 2014 finalist in New York, has reached the quarter-finals or better in his last five Grand Slam appearances.

Results

1st rd

Novak Djokovic (SRB x1) bt Roberto Carballes Baena (ESP) 6-4, 6-1, 6-4

Juan Ignacio Londero (ARG) bt Sam Querrey (USA) 3-6, 6-1, 7-6 (7/3), 7-5

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

Jeremy Chardy (FRA) bt Hubert Hurkacz (POL) 3-6, 6-3, 6-7 (6/8), 6-1, 6-4

Miomir Kecmanovic (SRB) bt Laslo Djere (SRB) 6-2, 6-1, 7-5

Paolo Lorenzi (ITA) bt Zachary Svajda (USA) 3-6, 6-7 (5/7), 6-4, 7-6 (7/4), 6-2

Reilly Opelka (USA) bt Fabio Fognini (ITA x11) 6-3, 6-4, 6-7 (6/8), 6-3

Dominik Koepfer (GER) bt Jaume Munar (ESP) 6-4, 7-6 (7/2), 5-7, 7-5

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

Hugo Dellien (BOL) bt Kwon Soon-woo (KOR) 6-3, 6-4, 2-6, 2-3 retired

Daniil Medvedev (RUS x5) bt Prajnesh Gunneswaran (IND) 6-4, 6-1, 6-2

Damir Dzumhur (BIH) bt Elliot Benchetrit (FRA) 4-6, 6-2, 6-3, 6-0

Dan Evans (GBR) bt Adrian Mannarino (FRA) 6-4, 6-3, 2-6, 6-3

Lucas Pouille (FRA x25) bt Philipp Kohlschreiber (GER) 6-3, 4-6, 6-4, 6-4

David Goffin (BEL x15) bt Corentin Moutet (FRA) 6-3, 3-6, 6-4, 6-0

Borna Coric (CRO x12) bt Evgeny Donskoy (RUS) 7-6 (9/7), 6-3, 6-0

Grigor Dimitrov (BUL) bt Andreas Seppi (ITA) 6-1, 6-7 (2/7), 6-4, 6-3

Pablo Cuevas (URU) bt Jack Sock (USA) 6-4, 7-5, 7-6 (7/5)

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