But after earlier slumping to first round defeats in Atlanta and Washington DC since starting preparations for the US Open, Venus isn't pushing the panic button.
"We have improved a lot from the last two weeks and have kept working on things so as long as we keep doing those things, it will click."
Despite their recent loss of form, the complicated tour rules mean Venus and Harrison they are almost certain to make it to London's season finale in November.
The tour finals feature eight teams playing round robin in two groups of four before the semi-finals and final. There is also a ninth team in London who are alternates and play if one of the teams pull out through injury.
The top seven teams in the 2017 ATP Doubles Team rankings qualify followed by up to two Grand Slam winners in order of their positions between 8 and 20 in the rankings.
There have been three different grand Slam winners this year with Wimbledon champions Lukasz Kubot and Marcelo Melo currently leading the race to London and Australian Open champions Henri Kontinen and John Peers second. Melo and Kubot have already qualified while Kontinen and Peers are all but guaranteed.
Venus and Harrison are currently fifth in the race but with only the US Open to come, it's almost certain at worst the Kiwi and American would go to London as a Grand Slam champion and even if they are not in the top seven teams, they will probably claim the final spot as the highest ranked Grand Slam champions not to automatically qualify.
Qualifying for London would be a massive achievement and would provide a huge financial carrot for Venus who would earn a share of 96,000 US dollars just for participating.
"I've said before that's our goal to play in London at the end of the year, we still have a lot of work to get there and we just have to try to get better going forward next week.