A marathon day ended for Venus and Routliffe just before 11pm (UK time) when they won their mixed doubles round-of-16 match in London.
The second-seeded Kiwi pair fought back to beat British duo Henry Patten and Olivia Nicholls 5-7, 7-5, 11-9 to advance to a quarter-final against another Briton, Neil Skupski, and American Desirae Krawczyk.
About 90 minutes earlier, Routliffe and women's doubles partner Gabriela Dabrowski won a hard-fought quarter-final over German Laura Siegemund and Czech Barbora Krejcikova 6-4, 6-7, 6-4.
The second seeds' semi-final is against the seventh-seeded American combination of Caroline Dolehide and Krawczyk.
Men's doubles ninth seeds Venus and Skupski dominated two one-sided tiebreaks to beat Germans Constantin Frantzen and Hendrik Jebens 7-6, 7-6 in their quarter-final.
They'll play another unseeded pair in the semi-finals - Patten and Greek Harri Heliovaara.
