"We got that break to finish off the first set and everything started to roll and feel good, and we played really well from there to close out the match. It was great but we are back out there tomorrow for a tough match," Venus said.
They will take on fifth seeds Jamie Murray and Bruno Soares in the second round early tomorrow morning New Zealand time. Murray and Soares have also qualified for London and are potential opponents in the round robin.
"We've played them a few times. We played them at Queens earlier this year, and I played Jamie (Murray) in the US Open Mixed doubles final and Bruno (Soares) just the other week in Stockholm. They have both been around a long time and know the doubles game very well. They work within their skill set very well and practice with each other a lot," Venus said.
Venus and Harrison are currently ranked 9th as a doubles team but qualify for London by virtue of winning a Grand Slam this year. A spot in the elite eight team field is reserved for a Grand Slam champion ranked between 8 and 20 in the rankings.
Venus says he and Harrison are feeling very relaxed as they build towards their first appearance at the World Tour Finals.
"Warming up today we felt good and were joking around on court and that keeps us relaxed on court and focused and brings out the best in us."
