NEW YORK—Angelique Kerber is enjoying the best season of her career and attributes her rise to world No. 2 to a simple realization: Less is more.

The Australian Open champion reeled off nine straight games dismissing Roberta Vinci, 7-5, 6-0, to reach her first Flushing Meadows semifinal since 2011.

US Open: Kerber Carves Up Vinci in Quarterfinals

The 28-year-old German said increasing the intensity of her practicing, while decreasing the time spent on court has benefited her immensely this season.

"I think my practice change a little bit," Kerber said. "I'm trying to focusing just on one or two things during the practice and really trying to focusing on this and improving few things and not making things also too complicated. To going out there and practicing like not maybe two hours, but just one hour, and full intensity. I think this is what I change.

"My game, I think my serve improved a little bit more than like few months ago. Of course that helps me a little bit more on my game style when my first serve cames more."

The experience of defeating world No. 1 Serena Williams in the Australian Open final and testing the 22-time Grand Slam champion in the Wimbledon final has made Kerber a much more confident player as well. She raised her record to 8-3 vs. Top 10 opponents this season.

"Now I'm a completely different player, I think," Kerber said.  "I'm going out. I have a lot of confidence. I know how to win big matches. I know how it feels playing on the stadium. I'm also enjoying it more than years ago.  I'm trying tog oing there and enjoying the atmosphere and also win the matches.

"I mean, years ago I came here and I had nothing to lose and my goal was playing good, and now my goal is winning the matches and this is a little bit different."