US Open 2019: Serena Williams storms into the fourth round

Six-time champion Serena Williams is safely through to the fourth round of the US Open after a routine victory over Czech Karolina Muchova.
The American won 6-3 6-2 after converting five of nine break points against the Wimbledon quarter-finalist.
Williams was broken back midway through the second set but it was an otherwise flawless display.
Second seed Ashleigh Barty is also through after a 7-5 6-3 win over Greek 30th seed Maria Sakkari.
And third seed Karolina Pliskova overcame a mid-match blip to beat Tunisia's Ons Jabeur 6-1 4-6 6-4.
The Czech 2016 finalist had been a set and a break up and had appeared to be cruising before Jabeur took a medical timeout early in the second set and won five games in a row to make a match of it.
Pliskova will face British number one Johanna Konta in the fourth round after the 16th seed defeated China's Zhang Shuai 6-2 6-3.
Williams, who is still seeking to equal Australian Margaret Court's all-time record of 24 Grand Slam singles titles, will play Croatian 22nd seed Petra Martic in round four.
Martic, a French Open quarter-finalist, defeated Latvian 12th seed Anastasija Sevastova 6-4 6-3 on court 10.
Coach Reno Manne gives tennis tips and advice on technique, movement and Triple Vision.