NEW YORK—Angelique Kerber says she is ready to assume her No. 1 ranking following her success this season.

The 28-year-old German officially ascended to the top this week after defeating Karolina Pliskova in the U.S. Open final. Kerber clinched the No. 1 spot when Serena Williams fell in the semifinals at Flushing Meadows, and then capped the achievement with a second Grand Slam title.

"It's big right now," she told a small group of reporters after beating Pliskova. "But I really feel it, because I [gave] everything this season. I won so many matches, tournaments, good matches. This is what I was working to reach."

Kerber is the oldest player to reach No. 1 for the first time. In her breakthrough season, she won the Australian Open and the U.S. Open, took home a silver medal at the Summer Olympics and reached the final of Wimbledon.

"I had a lot of up and down in my career, and right now I'm going my own way," she said. "Patience, discipline—giving everything on court … This is what I'm trying to bring in every single match."

She has also been concentrating on enjoying herself on court, rather than getting caught up in the race for No. 1.

"I had the pressure these two weeks because of all the questions," Kerber said. "Right now, I am trying to enjoy this moment because it's really special."