Fifth seed Steve Johnson reached the quarter-finals at the Citi Open in Washington DC with a 6-4, 6-4 victory over qualifier Ryan Harrison on Thursday (21st July).

Top seed John Isner beat 15th seed Marcos Baghdatis 7-6 (7-3), 6-2 in straight sets in the third round of the ATP Citi Open on Thursday (21st July) at the Rock Creek Park Tennis Center in Washington DC.

No. 2-seeded Gael Monfils overwhelmed No. 16 Borna Coric 6-2, 6-3 in third round action at the Citi Open on Thursday, 21 July.

Eighth seed Sam Querrey defeated Alexandr Dolgopolov of the Ukraine, 7-6, 6-3, Thursday (21 July) in third round action of the ATP 500 Citi Open.

Qualifier Ryan Harrison was on his season- best run at the Citi Open, ranked 158th in the world from a career-best 43rd in 2012- he came up against Steve Johnson- who will be part of the USA olympic team next month.

Johnson didn't face a single break point on his own serve.

The 26-year-old won the match with a 130 miles per hour ace.

He took a 6-4, 6-4 victory to end Harrison's run.

Elsewhere It was first against 15th in an all-seeded third round clash- John Isner against Marcos Baghdatis.

Top-seeded Isner, produced serves at up to 143 miles per hour, fired 16 aces and never faced a break point in a one-sided 7-6, 6-2 straight sets victory.

In the quarter- finals, this will be the third year in a row that Isner will now play fifth-seeded compatriot Steve Johnson in Washington.

It took just 54 minutes and 19 seconds for France's Gael Monfils to defeat Borna Coric 6-2, 6-3.

Monfils, the No. 2 seed, won 22 of his 23 first services and out-aced the Croatian 12-4.

Sam Querrey moved on to the quarterfinals with a win over Alexandr Dolgopolov.

Dolgopolov was the No. 11 seed in this tournament, but it was Querrey who went through-

He will next face the tournament's Gael Monfils, in the next round.