Roger Federer became the first three-time champion of the Cup of Chapman, and Switzerland for the fourth time won the exhibition tournament, second in wins only to team US, which has six titles.
The mixed doubles is played in a fast four format - the first team to four points wins, with a tie-break held if the scores are 3-3.
"Oh god. I mean, me and Angie (Kerber) after we lost past year, we were pretty disappointed and we immediately decided we wanted to come back and we wanted to compete again for our country at the Hopman Cup".
The world No.2 looked to be heading for a rapid victory, breaking Bencic's first two service games to race to a 3-0 lead.
"I'm one of the top 10 favourites and so are many others", he said.More news: United States jobs data, dovish Fed comments boost equities
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"We will remember for the Rest of our lives this week, especially at this last ball change", said Zverev, and known how much he and Kerber were eager to win the title this time. Bencic sealed a final love break of Kerber with a forehand victor, 4-0. "I'm a bit surprised the matches have gone as well as they have", the 37-year-old added.
It was not until Kerber's third match point that a backhand victor secured the 6-4, 7-6 (8/6) win.
"I will be excited to watch it tomorrow and see who we play in the final", Federer said.
Kerber had two match points at 6-4 in the tie-break, but Bencic again hung on grimly and won the next two points. "I think I only returned two of Federer's serves the whole match and the second one was the last point and the most important.", Sakkari said after the match.
Serena Williams, who has won the Hopman Cup twice in her five appearances, said it would be "heartbreaking" if the mixed-team event was axed as women would not be involved in the World Cup.
But the event appears doomed, due to the creation of a new ATP World Team Cup, which is set to be launched in Australia from January 2020.