Serena Williams fought back from a set down against Ana Ivanovic to reach the Bank of the West Classic semi-finals.
Steve Johnson's impressive run at the Citi Open in Washington came to an end after a loss to Milos Raonic.
The seemingly unstoppable David Goffin reached his first ever ATP World Tour final in Kitzbuhel.
Top seed Tomas Berdych was stunned by world number 36 Vasek Pospisil at the Citi Open in Washington.
Angelique Kerber survived a major scare to progress through to the quarter-finals of the Bank of the West Classic
Third seed Lukas Rosol suffered a quarter-final defeat to qualifier Maximo Gonzalez at the bet-at-home Cup Kitzbuhel.
Two-time Grand Slam champion Li Na is out of next month's US Open because of a knee injury.
Tomas Berdych lived up to his billing in the second round of the Citi Open in Washington with a win over Robby Ginepri.
Serena Williams made a winning return to action by beating Karolina Pliskova at the Bank of the West Classic.
Marina Erakovic safely made it through to the third round of the Citi Open with a comfortable win over Shelby Rogers.