Serena Williams returned to action for the first time since pulling out of Wimbledon with a straight-sets win over Karolina Pliskova in Stanford, USA.
The world number one had to retire from a doubles match with her sister, Venus, at Wimbledon on 1 July with what proved to be a virus.
Williams, 32, saw off Karolina Pliskova of the Czech Republic 7-5 6-2 at the Bank of the West Classic.
Williams won the title on her last two appearances in Stanford in 2011 and 2012, and has now won 10 consecutive matches at the Californian event
Williams had taken some time off after Wimbledon, recuperating with a holiday in Croatia before returning to practice.
After losing in the second round of the French Open and the third round of Wimbledon, she will defend her US Open title next month.
The 17-time Grand Slam champion will play fifth seed Ana Ivanovic or Canadian qualifier Carol Zhao in the Stanford quarter-finals.
Second seed Agnieszka Radwanska suffered a surprise 6-3 3-6 6-4 defeat by world number 59 Varvara Lepchenko of the USA.
In Washington, Britain’s Jocelyn Rae and Anna Smith beat top seeds Cara Black and Sania Mirza 6-4 6-3 to reach the semi-finals of the Citi Open.