US Open at a glance -- day 1

US Open at a glance -- day 1: Headlines + Halep becomes first top seed to lose in US Open in first round + Serena sprints through opener + Champion Nadal sends injured friend Ferrer into Slam retirement + Murray, Wawrinka return with victories + Defending champion Stephens into 2nd round Top results -- Kaia Kanepi (EST) bt Simona Halep (ROM x1) 6-2, 6-4 -- Serena Williams (USA x17) bt Magda Linette (POL) 6-4, 6-0 -- Rafael Nadal (ESP x1) bt David Ferrer (ESP) 6-3, 3-4 - retired -- Andy Murray (GBR) bt James Duckworth (AUS) 6-7 (5/7), 6-3, 7-5, 6-3 -- Stan Wawrinka (SUI) bt Grigor Dimitrov (BUL x8) 6-3, 6-2, 7-5 Sidelines One streak ends... -- America's Jack Sock won his first match since May and ended a four-match first round losing streak at the Slams with a 6-0, 7-6 (7/4), 6-2 victory over Guido Andreozzi of Argentina. ...and another one -- Poland's Agnieszka Radwanska had never lost in the first round at the US Open in her 12 previous visits. However, on Monday, that proud run ended when she lost 6-3, 6-3 to Germany's Tatjana Maria. Walk of fame -- Garbine Muguruza admits she's not a fan of the hustle and bustle of New York and prefers not to venture too far away from her hotel during the US Open. "I feel like people are going to walk over me. It's like, Man, seriously," said the former French Open and Wimbledon champion. With friends like these... -- Greek teenager Stefanos Tsitsipas told an over-enthusiastic fan in the crowd in his win over Tommy Robredo to shut-up - and then revealed it was a friend of his. "It was one of my friends that came from Australia to support me. When you're concentrated during a match, you're trying to manage things, go with your tactics, and someone starts screaming from outside, Go to T or wide, it just plays with your mind," said Tsitsipas who was only three when veteran Robredo made his New York bow in 2001. Record crowds, say organisers -- The US Open kicked off its 50th anniversary by setting an all-time single-day attendance record of 67,832, organisers said. The day session drew 40,541 fans while the night session brought in 27,291. Who's saying what "Normally they cheer for the underdog. Now they cheer for her. It was a bit annoying for some time, but I got over it." -- Kaia Kanepi after beating world number one Simona Halep "I'm happy I was first on there, even if I lost." -- Halep after her match, the first played on the new Louis Armstrong Stadium "I was getting a monkey off my back. Felt like King Kong was on my back there for a while." -- Jack Sock on winning his first singles match since May "I told him at the net, look we're going to be back here, we're going to be playing in the finals. We will have so many of these". -- Denis Shapovalov to Canadian teammate and friend Felix Auger-Aliassime who was forced to retire after suffering what appeared to be an irregular heartbeat.