Three weeks on from that shock second-round defeat in New York, Muguruza leveled the score in emphatic fashion breaking five times during a 6-3, 6-3 victory. In the quarterfinals the top seed will face Elina Svitolina after she saw off No.8 seed Anastasia Pavlyuchenkova, 7-6(5), 6-4.
Muguruza has made it at least as far as the quarterfinals on each of her previous visits to the Japanese capital, but this time is expecting to stay even longer. Seeded No.1, the Spaniard benefited from a first-round bye and looked suitably acclimatized against Sevastova.
A typically assertive baseline assault enabled Muguruza to build an early lead, breaking in the third game when she thumped a forehand onto the back of the baseline. Although Sevastova leveled the set at 3-3, Muguruza seized back the momentum by rattling off the next three games.
The second set followed a similar pattern, the World No.3 finishing the stronger, completing her revenge mission when Sevastova pulled a backhand into the tramlines.
"Maybe there was a little bit of pressure. But I'm so happy that I came back as top seed, because it means that I'm improving and hopefully I can be in the final," Muguruza said.
"It was a surprise for me. The last match I played was against her and I guess this time I had my revenge, but this is tennis."