Guillermo Garcia-Lopez and Federico Delbonis both crashed out unexpectedly in the second round of the Swiss Open.
Home favourite Marin Cilic cruised through to the quarter-finals at the Croatia Open with victory over Igor Sijsling.
France's Pauline Parmentier upset the odds by beating eighth-seed Slovak Jana Cepelova in the Baku Cup.
Our Andy Schooler says there's something not right about Victor Troicki's wild card in Gstaad this week.
Robby Ginepri claimed his first ATP World Tour win in over a year to advance into the second round of the Atlanta Open.
Igor Sijsling beat Julian Reister to set up a second-round clash with third seed Marin Cilic at the Croatia Open.
Reigning champion Mikhail Youzhny will begin his Credit Agricole Swiss Open defence against Kenny de Schepper.
Heather Watson was broken seven times as she was dumped out of the first round of the Baku Cup by Kristina Mladenovic.
Top seed Sorana Cirstea overcame her recent shoulder problems to beat Ons Jabeur in the first round of the Baku Cup.
Sam Querrey safely reached the last 16 of the BB&T Atlanta Open but two American hopefuls failed to qualify.