Venus will be ranked eighth and Klaasen just ahead of him at seven.
They are on track to make the ATP Finals in London for the second straight year together having climbed to second in the race, moving ahead of the world's most well-known team, the Bryan brothers Bob and Mike. Venus and Klaasen have been incredibly consistent in recent months with their Halle title win, reaching the Wimbledon semifinals and now the Washington title.
Due to Visa problems for Klaasen getting into Canada they aren't able to play this week's Montreal ATP Masters 1000 tournament together however.
Venus is instead teaming up with Artem Sitak's former partner Austin Krajicek and they are unseeded. They face the Austrian pair of Jurgen Melzer and Oliver Marach in the first round. Venus and Klaasen will resume their partnership the following week in Cincinnati in their final hit out before the US Open.
The other Kiwi in Montreal is Marcus Daniell who has teamed up with Serbia's Laslo Djere. They will face Canadian wildcards Peter Polansky and Brayden Schnur.