Karlovic a step away from back-to-back titles

Ivo Karlovic downed Steve Johnson in the semi-finals of the Citi Open as he looks to claim his second title in as many weeks.

The big-serving Karlovic continued his impressive run of not surrendering a break of serve this week at the Rock Creek Park Tennis Center, as he beat Johnson 6-4, 6-4 to set up a final showdown with Gael Monfils.

Johnson, who ousted top seed John Isner in the quarter-finals, had no answers as Karlovic threw down 14 aces to take his total to the tournament to 80. 

Having won last week at the Hall of Fame Championships in Newport, the 37-year-old is now in line to win consecutive titles and once again set a new mark for the oldest winner on Tour.

Monfils will have something to say about that though, with the Frenchman seeing off the challenge of young gun Alexander Zverev 6-4, 6-0 in his semi-final.

The Frenchman needed just an hour to defeat the up-and-coming German, dropping just three points on his serve in the second set.

Monfils is gunning for his first Tour title since winning in Montpelier in 2014.