of Croatia will be aiming to make a great run at the US Open in Flushing Meadows New York and perhaps beat some of the world best players.
In 2008 Karlovic achieved one of the best wins in his career when he beat Roger Federer in the 3rd round of the ATP Masters event in Cincinnati Ohio.
Karlovic also beat the then world number 1 Lleyton Hewitt of Australia in the 1st round of Wimbledon in 2003.
Last year Federer lost in the US Open final in 5 sets against Juan Martin Del Potro of Argentina 3-6 7-6 4-6 7-6 6-2.
It was a 1st Grand Slam title for Del Potro who also beat Rafael Nadal in the Semi Finals, 6-2 6-2 6-2.
Federer is a 5 time champion at the US Open he last won the title in 2008 when he beat Andy Murray in the final in straight sets.