MASON, Ohio (AP) — Roger Federer took a first step toward a seventh Cincinnati title on Tuesday night, beating Roberto Bautista Agut 6-4, 6-4 in his opening match.

The Swiss star won the Western & Southern Open last year. He easily handled the Spaniard, whom he has beaten in straight sets in all four of their career matches.

John Isner’s summer surge ended with an opening-round loss to friend and doubles partner Sam Querrey, leaving the top-ranked American with some things to work out before the U.S. Open. Querrey was steady throughout a 6-3, 7-6 (3) win over the 11th-seeded Isner, the first upset on the men’s side.

On the women’s side, Venus Williams withdrew from her evening match because of illness.

___

Follow Joe Kay on Twitter: http://twitter.com/apjoekay

Sam Querrey, right, shakes hands with John Isner at the end of their first round match at the Western & Southern Open tennis tournament, Tuesday, Aug. 18, 2015, in Mason, Ohio. Querrey defeated Isner, 6-3, 7-6 (3). (AP Photo/David Kohl)

http://aimmedianetwork.com/wp-content/uploads/sites/22/2015/08/web1_105298862-745332abd995423abe7dc70e7d8b1999.jpgSam Querrey, right, shakes hands with John Isner at the end of their first round match at the Western & Southern Open tennis tournament, Tuesday, Aug. 18, 2015, in Mason, Ohio. Querrey defeated Isner, 6-3, 7-6 (3). (AP Photo/David Kohl)

John Isner returns a shot from Sam Querrey during a first round match at the Western & Southern Open tennis tournament, Tuesday, Aug. 18, 2015, in Mason, Ohio. (AP Photo/David Kohl)

http://aimmedianetwork.com/wp-content/uploads/sites/22/2015/08/web1_105298862-9a3e589f08e1465a99646ff5e59dcb10.jpgJohn Isner returns a shot from Sam Querrey during a first round match at the Western & Southern Open tennis tournament, Tuesday, Aug. 18, 2015, in Mason, Ohio. (AP Photo/David Kohl)

Sloane Stephens, of the United States, returns the ball to Carla Saurez Navarro, of Spain,during a first round match at the Western & Southern Open tennis tournament, Tuesday, Aug. 18, 2015, in Mason, Ohio. (AP Photo/David Kohl)

http://aimmedianetwork.com/wp-content/uploads/sites/22/2015/08/web1_105298862-a13d33fdb8624651ac1930562fa61c8d.jpgSloane Stephens, of the United States, returns the ball to Carla Saurez Navarro, of Spain,during a first round match at the Western & Southern Open tennis tournament, Tuesday, Aug. 18, 2015, in Mason, Ohio. (AP Photo/David Kohl)