Three days after turning 40, Gael Monfils has walked off a Grand Slam court for the last time. The Frenchman, a crowd favourite at Flushing Meadows for 21 years, lost to Learner Tien, 20 years his junior. Monfils says his next chapter will be in finance, having already signed to work in wealth management for a Swiss company. Top seed Alexander Zverev needed another five-set battle to beat unseeded Frenchman Quentin Halys and reach the third round, calling his own performance poor despite the win, in a match that again finished in the early hours. Coco Gauff, a two-time Grand Slam champion, beat Paula Badosa in straight sets, saying she still sees room to improve her forehand. Francisco Cerundolo advanced despite visible frustration and will face local favourite Taylor Fritz next. Subscribe to our channel: http://bit.ly/AJSubscribe Follow us on Twitter: https://twitter.com/AJEnglish Find us on Facebook: https://www.facebook.com/aljazeera Check our website: http://www.aljazeera.com/ Check out our Instagram page: https://www.instagram.com/aljazeeraenglish/ Download AJE Mobile App: https://aje.io/AJEMobile #USOpen #Tennis #GaelMonfils #AlexanderZverev #CocoGauff #FlushingMeadows #GrandSlam #Sports #NewYork #AlJazeeraEnglish