Federer, Bencic put their team knowledge to the test

Hopman Cup teammates Belinda Bencic and Roger Federer—known as #Benderer—took a quiz to see how well they knew each other. It turns out they both have a little bit to learn...

For example, Federer knew that Bencic's father was named Ivan, but didn't know that her mother's name was Dana.

Later, at the New Year's eve gala, the 37-year-old would joke that he is old enough to be Bencic's dad:

Federer also guessed that Bencic played her first Fed Cup tie in 2015. The answer was 2012. He did know, however, that his partner won WTA 125K titles this fall in Thailand and Taiwan.

"I've been checking on her, making sure her form is in check," Federer said jokingly.

Bencic, when it was her turn to answer questions about Federer, knew the ages of his two sets of twins: 8 and 3.

But when asked to name Federer's three idols, she could only come up with one: Pete Sampras. The other two, in case you're playing along, are Boris Becker and Stefan Edberg.

Last, Bencic didn't know that the University of Basel had given Federer an honorary doctorate in medicine.

"You can call me Dr. Federer if you want," Federer said.

Switzerland kicked off their Hopman Cup by sweeping Japan 3-0 in their first tie.