The Citi Open has been known for its humid D.C weather. There have been rain delays, the courts are slick, and the balls move fast during the day when the sweltering sun is out. These conditions are no surprise for the players who have made their way through to the semifinals of the Citi Open. What is surprising though, is the tennis that spectators have gotten to see.

After Kevin Anderson had upset Dominic Thiem, not many people expected another twist in the natural hierarchy that you see throughout the tennis circuit. Jack Sock of the United States would be the player to surprise the crowds once again with his victory over Milos Raonic in straight sets, 7-5, 6-4.

Jack Sock serves like a machine to beat Roanic

Jack Sock and Milos Raonic are both big servers, but Jack Sock would have the upper hand with not only his serve being both powerful and consistent but also defending superbly during Raonic's serving games, which allowed him to break the Canadian three times.

Sock is in prime form. While usually, only his serves would click and his ground stroke game would be suspect, this year at the Citi Open he has been able to prove that he can play both offensively and defensively to win. In his last two matches, Sock has managed to keep first serve percentage well over 75 percent.

Even though Sock played extremely well, the match was close, with Sock only winning three more points than Ranoic by the end of the match.

"We've always had big matches," reflected Sock. Sock would then go on to talk about how he managed to save five games where he was 30-0 down. If by chance Sock had lost those games, the match would have turned out to be extremely different.

Sock confident on home ground

Jack Sock loves the Citi Open, for reasons similar to why a high school football team prefers to play at 'home' rather than 'away.' In Washington D.C the crowd is on Sock's side, and they give him that extra encouragement and confidence that he needs to fight through his matches, something he will need when he plays his semifinal match against Kevin Anderson.

".. we don't have the privilege of playing in front of our home fans," says Sock. All the high-level tournaments in the United States take place during the hard court season, which begins around August.

Kevin Anderson is another big server, and Sock will have to play as well, or maybe even better than he did when he defeated Raonic. If all goes well, the American may hear his name being chanted throughout the Citi Open stadium.