World No. 1 Angelique Kerber will leave Melbourne this time without the coveted trophy. The reigning Australian Open champion suffered a fourth round loss to CoCo Vandeweghe that also has implications for the WTA top ranking.

Australian Open: Vandeweghe Knocks Out Defending Champ Kerber

Vandeweghe easily defeated Kerber 6-2, 6-3 Sunday night in a match that was all one-way traffic right from the start. Vandeweghe outhit Kerber with a total of 30 winners as the German struggled to keep up.

“Yeah, it was a tough match, and of course I'm disappointed. But I was not feeling the ball at all tonight. I was not playing good from the first point,” Kerber said afterwards. “So, yeah, it was not my day and not my match, for sure.”

With Kerber’s loss, Serena Williams who the German beat in last year's final, could retake the top WTA ranking if she wins the the title outright.

2016 was a breakthrough year for Kerber. She won both the Australian Open and US Open along with clinching the year-end top ranking.

But Kerber entered this year’s Australian Open facing many questions on how she would handle being No. 1 in the world at a Grand Slam for the first time in her career. Early losses in the warm-up events in Brisbane and Sydney leading up to Melbourne suggested that 29-year-old German may have not found her A-game in time.

Kerber didn’t find that to be an issue when asked about it.

“No, my preparation was like I wanted and everything was fine. I came here to play good tennis, playing round by round, trying to continue my run from last year,” Kerber said. “But this is tennis, and you have good days and bad days. For sure today was not my best day.”

Kerber can now only look ahead to the rest of the season.

“Of course, they are new experiences. This is good, they are new challenges. I can learn from all the other stuff which is new for me. Yeah, I mean, let's see. It's just the beginning of the year. I can still improve my tennis, which is good. I will try my best to, yeah, of course, coming back stronger.”

When asked who might win the title now, Kerber would only say that the one left standing on the final Saturday would deserve it.

“I don’t know, I mean the best will win at the end.”