Serena teams with John Isner for Hopman Cup

Serena and John Isner will team up to represent the U.S. in next January's Hopman Cup in Perth, Australia. Isner is best known for playing the longest match in tennis history at this year's Wimbledon, shattering multiple records in his 11 hour, five minute marathon that spanned the course of three days.

The Hopman Cup will run from 1/1 - 1/8 of next year. Unlike other national team tennis tournament events, the Hopman Cup is unique in that it combines male and female players. The field for next year's tournament is packed with some of the world's best. Right now, there are five Grand Slam champions confirmed to play.

Nations are split into two groups where they will play a men's singles match, a women's singles match and then a mixed doubles match in a round-robin format. The respective group winners advance to a tournament final against each other. The tournament is played on hard court and allows players to prepare for the upcoming Australian Open.