U.S. Open Day 4Updated 2200 GMT (0600 HKT) September 1, 2016 Chat with us in Facebook Messenger. Find out what's happening in the world as it unfolds. Photos: U.S. Open continues Rain hit New York on Thursday, which made for unplayable outer courts for a time. But thankfully there was a roof over center court this year ...Hide Caption 1 of 6 Photos: U.S. Open continues Simona Halep was the first to take to the court under the roof due to the early rain and beat a fellow French Open finalist, Lucie Safarova, 6-3 6-4. Hide Caption 2 of 6 Photos: U.S. Open continues Andy Murray followed and also advanced in straight sets. But the second seed was tested by Spain's Marcel Granollers. Hide Caption 3 of 6 Photos: U.S. Open continues In 2 1/2 hours, Murray, tennis' most in-form player, progressed 6-4 6-1 6-4. Hide Caption 4 of 6 Photos: U.S. Open continues Venus Williams, the seven-time grand slam winner, ended the day session on Ashe by easing past Germany's Julia Goerges 6-2 6-3. Hide Caption 5 of 6 Photos: U.S. Open continues Among matches completed on the other courts when the rain relented, 2014 finalist Kei Nishikori fended off big-hitting Russian Karen Khachanov 6-4 4-6 6-4 6-3. Hide Caption 6 of 6Rain played havoc with the schedule at the U.S. Open on Thursday -- but the new roof ensured play continued on the main Arthur Ashe stadium. More from Sport - TennisSanchez-Casal Academy: The making of Andy MurrayMaria Sharapova: Russian wins on return from 15-month doping banMaria Sharapova's comeback leaves women's Tour dividedSerena Williams slams Ilie Nastase over 'racist' commentsCan Serena Williams return to the top of tennis after giving birth?