The Japanese pair will next face top seeds Mektic/Pavic after the Croatians also advanced
McLachlan and Nishikori, who are playing together for just the second time this week, broke twice and won 88 per cent (30/34) of their first-service points to advance in 81 minutes.
They will next face top seeds Nikola Mektic and Mate Pavic after the Croatians battled past Italians Lorenzo Musetti and Lorenzo Sonego 7-5, 6-7(5), 10-7. Mektic and Pavic have won eight tour-level titles this year, including three ATP Masters 1000s and Wimbledon.
Djokovic Marches Through In Tokyo
The top seeds, who also became the first team to qualify for the 2021 Nitto ATP Finals earlier this month, saved both breaks they faced to claim victory in two hours and six minutes.
Colombians Juan Sebastian Cabal and Robert Farah also booked their spot in the last eight with a 6-4, 6-1 truimph over Austrians Oliver Marach and Philipp Oswald. The third seeds have lifted two tour-level titles this season at the Barcelona Open Banc Sabadell and the Dubai Duty Free Tennis Championships.