Which Swiss player partnered Federer to Hopman Cup titles in 2018 and 2019?

Belinda Bencic partnered Roger Federer when Switzerland won the Hopman Cup in 2018 and 2019.

The Hopman Cup was a mixed-team event in which nations fielded one man and one woman, with singles and mixed doubles matches deciding each tie. Federer and Bencic formed Switzerland's team for both editions, combining Federer's veteran experience with Bencic's rising singles career.

In 2018, they defeated Germany's Alexander Zverev and Angelique Kerber in the final. They successfully defended the title in 2019, again beating Germany in the championship match. The second triumph was Federer's third Hopman Cup title, the most won by any player in the event's history at that time.

The 2019 tournament also featured Federer's first competitive meeting with Serena Williams, who represented the United States. Federer and Bencic won their mixed-doubles match against Williams and Frances Tiafoe. Martina Hingis is another famous Swiss tennis name, but she was not Federer's partner for these two Hopman Cup titles.