Wimbledon champion, Kerber then overcame Bencic 6-4 7-6 to level the tie.
Federer first won the Hopman Cup back in 2001 against the US when he was paired win Martina Hingis, he then claimed his second title alongside Bencic past year also against Germany.
The former world No.1 is now unbeaten in all her seven of her singles matches at the Hopman Cup.
As if beating Federer is not flattering enough for Tsitsipas, he now sits 15th in the world tennis rankings, sitting 12 spots behind Federer, and wins like this against one of the best players of all time will do wonders for the 20-year-old's quest to being ranked the number one player in the world.
But the 37-year-old played down his chances of winning in Melbourne, saying that he was just one of many challengers for the title with Djokovic the clear favourite despite his shock defeat to Roberto Bautista Agut in Doha this week.
Earlier, Spanish star Garbine Muguruza collected her first singles win over the new season, but also picked up a thigh injury that forced her out of the mixed doubles as Spain beat France 2-1.
"We really wanted to win as a team", Zverev said.
"I just played mixed, stood in the corner and watched her return all of the guys' serves".
Zverev's intensity dropped in the second set with Federer getting to a 3-0 lead before taking the final set 6-2 and ultimately the first game of the night. "She did it", he said, pointing at Bencic and making it clear she was making him laugh. In the hard-fought tie-break Kerber then used their third match ball.
"It was a hard one", Barty said post-match.
Kerber, who earlier this week beat Garbine Muguruza and Alize Cornet, broke twice - but also saved four break points in the second set to beat an error-prone Barty.