They have won six titles together in 2017.
Kubot and Melo will end the year ranked number one and Venus is under no illusions as to the difficulty of the task they face.
"They have taken their game to another level since we played them at Roland Garros." Venus said.
"But Ryan and I have gained a lot of confidence with each match this weekend believe and trust in our abilities so we are looking forward to a tough match tomorrow."
Venus and Harrison will hold no fears after impressive wins over Kontinen and Peers, Pierre Hugues-Herbert and Nicholas Mahut and Jean-Julien Rojer and Horia Tecau.
Venus and Harrison are still on track to win a staggering $486,000 US dollars for going through the tournament unbeaten. They have already earned US $94,000 dollars for participating in the tournament plus $36,000 for each round robin match win.
If they win their semi-final they will earn another $96,000 US dollars and an additional $188,000 for winning the tournament.
Venus and Harrison play their semi-final at 1am New Zealand time.