Eagle-eyed Instagram users spotted the former World No.1 leaving a comment on the WTA's Instagram page that left little doubt as to which player she thought had the best season, and it's no surprise who she voted for.
? WTA Insider (@WTA_insider) October 14, 2016
Did you catch it? Here's who Serena voted for in the 2016 WTA Player Of The Year award:
The comment comes as no surprise, as the pair's fierce rivalry this year has played out across two Grand Slam finals, with Kerber winning her maiden major title at the Australian Open and Serena later getting her revenge at Wimbledon in her record-tying 22nd Grand Slam title.
Kerber finally unseated Serena as the WTA World No.1 in September after the German won the US Open, but Serena had foreseen her rise much earlier than that.
After her loss in the final in Melbourne back in January, an introspective Serena was asked about Kerber's rise to World No.2, and she had this to say:
QUESTION: Pretty deserved No. 2 in the world now?
SERENA WILLIAMS: I think so. I mean, she's had a great month. She got to the finals in Brisbane. She won here. So, yeah. I was surprised and really happy for her. I'm like, Whoa, No. 2.
What's after 2 is 1, so I guess I better be careful (laughter).