The Japanese sixth seed, who fell to Marin Cilic in the 2014 final, quashed German Benjamin Becker's rally attempt, emerging with a 6-1, 6-1, 3-6, 6-3 victory on the new Grandstand court in two hours 10 minutes.

"It was a great feeling of course," Nishikori said of the lively reception he received from fans. "I have great memories here and I always love coming back to New York."

Nishikori appeared to be on his way to a quick victory when he put away the first two sets in 49 minutes.

But things then got complicated against the 96th-ranked Becker.

"When he's on he can really be aggressive from the serve, and second ball here he was attacking really well. He is always a dangerous player."

Nishikori, however, finally gained the break he needed for a 5-3 lead in the fourth and served it out with a love game punctuated by his seventh ace.

The second day of action at the year's final Grand Slam was set for a blockbuster night on the Arthur Ashe stadium court where Serena Williams was to launch her bid for a seventh US Open title against Russian veteran Ekaterina Makarova before second-seeded Briton Andy Murray took on Czech Lukas Rosol.

Williams's Wimbledon triumph in July saw her equal Steffi Graf's Open Era record of 22 major titles.

She has won four of five encounters with Makarova, including two US Open matches against the Russian left-hander.

Murray is bidding to become the fourth man in the Open Era to reach all four major finals in a calendar year. 

Since capturing his second Wimbledon title Murray has gone on to defend his Olympic gold in Rio, and he'll aim to build on that momentum in the tournament where his 2012 triumph made him the first British man to win a Grand Slam since Fred Perry at the 1936 US Open.

Murray will also be aiming to improve on his 2015 showing in Flushing Meadows, where his streak of 18 straight Grand Slam quarter-finals was snapped by Kevin Anderson.

Murray has downplayed any grudge match aspect to his clash with Rosol, who provoked an angry outburst from the Briton when they met in the quarter-finals at Munich last year.

In other early matches, third-seeded Swiss Stan Wawrinka faced a tricky first-round contest against former top-10 player Fernando Verdasco of Spain.

Verdasco has won three of their five encounters, including a straight-sets win in June on the grass courts at Queen's Club.
Sixth-seeded Venus Williams, who counts two US Open titles among her seven Grand Slam singles crowns, takes on 93rd-ranked Ukrainian Kateryna Kozlova.

The elder Williams sister will be making a record-setting 72nd main draw appearance in a Grand Slam.

Results from the second day of the 2016 US Open tennis championships at Flushing Meadows on Tuesday:

1st rd

Dominic Thiem (AUT x8) bt John Millman (AUS) 6-3, 2-6, 5-7, 6-4, 6-3
Pablo Carreño-Busta (ESP) bt Ilya Ivashka (BLR) 6-0, 7-5, 6-2
Janko Tipsarevic (SRB) bt Sam Querrey (USA x29) 7-6 (7/4), 6-7 (0/7), 6-3, 6-3
Steve Johnson (USA x19) bt Evgeny Donskoy (RUS) 4-6, 1-6, 7-6 (7/2), 6-3, 6-3
Juan Martín Del Potro (ARG) bt Diego Schwartzman (ARG) 6-4, 6-4, 7-6 (7/3)
Fabio Fognini (ITA) bt Teimuraz Gabashvili (RUS) 6-7 (9/11), 3-6, 7-6 (7/5), 7-5, 6-4
David Ferrer (ESP x11) bt Aleksandr Dolgopolov (UKR) 6-5 - retired
Nick Kyrgios (AUS x14) bt Aljaz Bedene (GBR) 6-4, 6-4, 6-4
Horacio Zeballos (ARG) bt Florian Mayer (GER) 6-3, 6-4, 7-6 (9/7)
Damir Dzumhur (BIH) bt Bernard Tomic (AUS x17) 6-4, 6-3, 4-6, 7-6 (7/0)
Alexander Zverev (GER x27) bt Daniel Brands (GER) 3-6, 6-1, 6-4, 7-6 (7/4)
Daniel Evans (GBR) bt Rajeev Ram (USA) 6-2, 4-6, 7-5, 6-1
Alessandro Giannessi (ITA) bt Denis Kudla (USA) 0-6, 6-4, 6-1, 1-6, 6-0
Stan Wawrinka (SUI x3) bt Fernando Verdasco (ESP) 7-6 (7/4), 6-4, 6-4
Kei Nishikori (JPN x6) bt Benjamin Becker (GER) 6-1, 6-1, 3-6, 6-3
Karen Khachanov (RUS) bt Thomas Fabbiano (ITA) 6-3, 6-3, 4-6, 6-3
Paul-Henri Mathieu (FRA) bt Christian Harrison (USA) 6-0, 6-2, 6-1
Nicolas Mahut (FRA) bt Philipp Kohlschreiber (GER x25) 6-3, 7-5, 1-0 - retired
Ivo Karlovic (CRO x21) bt Lu Yen-Hsun (TPE) 4-6, 7-6 (7/4), 6-7 (4/7), 7-6 (7/5), 7-5
Donald Young (USA) bt Jan-Lennard Struff (GER) 6-3, 7-5, 4-6, 7-5
Viktor Troicki (SRB) bt Radu Albot (MDA) 5-7, 3-6, 6-4, 6-4, 7-6 (7/5)
Jared Donaldson (USA) bt David Goffin (BEL x12) 4-6, 7-5, 6-4, 6-0
Feliciano Lopez (ESP x16) bt Borna Coric (CRO) 3-4 - retired
João Sousa (POR) bt Víctor Estrella (DOM) 6-0, 6-1, 6-1
Jérémy Chardy (FRA) bt Michael Mmoh (USA) 6-4, 6-4, 6-1
Grigor Dimitrov (BUL x22) bt Inigo Cervantes (ESP) 6-2, 6-4, 7-6 (9/7)
Gilles Simon (FRA x30) bt Radek Stepanek (CZE) 6-3, 6-1, 6-4
Paolo Lorenzi (ITA) bt Carlos Berlocq (ARG) 6-4, 6-2, 6-1
Marcel Granollers (ESP) bt Juan Monaco (ARG) 7-6 (7/5), 7-6 (7/2), 6-4