Andy Murray claimed a comfortable straight sets win over German qualifier Mathias Bachinger in a windy night session at Flushing Meadows on Thursday.
Earlier in the day, their were surprise wins for American Sam Querrey and 23-year-old Andrey Kuznetsov, but top seed Novak Djokovic kept his bid for a second title alive.
There were also wins for America’s John Isner, Japan’s Kei Nishikori and Jo-Wilfrield Tsonga of France.
Arthur Ashe Stadium
 Andy Murray (GBR) beat Matthias Bachinger (GER) 6-3 6-3 6-4
British number one Murray was a mismatch for Bachinger en route to a 6-3 6-3 6-4 dismantling in a half-empty Stadium.
Murray’s 36 winners was 12 more better than his 235th-ranked opponent, complemented by his 7 times lesser unforced error, as the 2012 champion sealed his passage to the third round in 1 hour 46 minutes.
“I hope I feel better every day now,” said Murray, who was troubled by a lingering fitness concerns in his first round against Robin Haase.
“I felt fine the last couple days and had no problems on the Tuesday or Wednesday. I practised well and didn’t have any problem. Tonight was fine too.”
The 27-year-old Scot will face 97th-ranked Russian Kuznetsov, who deflated No. 31 seed Fernando Verdasco of Spain 6-3 4-6 4-6 7-5 6-3 in the next round.
 Novak Djokovic (SRB) beat Paul-Henri Mathieu (FRA) 6-1 6-3 6-0
World number one Djokovic lost just four games on his way to a 6-1 6-3 6-0 demolition of Frenchman Paul-Henri Mathieu.
The power and precision of his serves matched that of his groundstrokes, as the Serb went on to hit 13 aces and 33 winners in under an hour-and-a-half.
Up next will be home-grown tyalent Sam Querrey (ranked 67), who came up with the minor upset of Day 4 after beating Spaings No. 28 seed Guillermo Garcia-Lopez 6-3 6-4 6-4.
“I have nothing to complain about,” said the 2011 champion, when asked if he would have liked a longer workout. “I wanted to get my job done as quick as possible. I don’t have to play long matches to get into my groove.”
 Jo-Wilfried Tsonga (FRA) beat Aleksandr Nedovyesov (KAZ) 6-3 6-4 6-4
Frenchman Tsonga also dominated his second round tie with Kazakh Aleksandr Nedovyesov to win 6-3, 6-4, 6-4 in an hour and 47 minutes.
The 9th seed served 13 aces (battering the speedometer at a high of 139mph) and 38 winners past Nedovyesov, who failed to withstand with his opponent’s power in a windy condition.
Up next for Tsonga is a third round match against Spaniard Pablo Carreño Busta, who took four sets to down Tsonga’s compatriot Benoît Paire -1 6-4 3-6 6-3.
 Milos Raonic (CAN) beat Peter Gojowczyk (GER) 7-6(4) 5-7 6-4 7-6(3)
 Kei Nishikori (JPN) beat Pablo Andujar (ESP) 6-4 6-1 ret.
 John Isner (USA) beat Jan-Lennard Struff (GER) 7-6(5) 6-4 6-2
 Tommy Robredo (ESP) beat Simone Bolelli (ITA) 5-7 6-7(5) 6-4 6-3 6-2
 Philipp Kohlschreiber (GER) beat Michael Llodra (FRA) 6-2 ret.
 Leonardo Mayer (ARG) beat Matthew Ebden (AUS) 6-1 6-3 6-4
Sam Querrey (USA) beat  Guillermo Garcia-Lopez (ESP) 6-3 6-4 6-4
Andrey Kuznetsov (RUS) beat  Fernando Verdasco (ESP) 6-3 4-6 4-6 7-5 6-3
Nick Kyrgios (AUS) beat Andreas Seppi (ITA) 6-4 7-6(2) 6-4
Pablo Carreno Busta (ESP) beat Benoit Paire (FRA) 6-1 6-4 3-6 6-3
Victor Estrella Burgos (DOM) beat Borna Coric (CRO) 7-6(2) 4-6 6-4 6-2