Gael Monfils and the in-form Ivo Karlovic will meet in the Citi Open final after straight-sets wins in Washington. Monfils, the second seed at the ATP 500 event, cruised past German Alexander Zverev 6-4, 6-0.

The French 2011 runner-up needed just one break in the first set before losing only seven points in the second, wrapping up victory in an hour. Monfils is into his 25th ATP World Tour final, with a chance to improve his poor 5-19 win-loss record in deciders.

Awaiting him is the red-hot Karlovic, who sent down 14 aces in a 6-4, 6-4 win over Steve Johnson. The Croatian 13th seed is on an eight-match winning run, having won the Newport title last week.

Johnson failed to convert his five break points as Karlovic advanced to his 16th ATP final. Karlovic has seven titles to his name, and he has won two of four previous meetings against Monfils.