Britain's James Auckland continued his run at the Mumbai Open with a battling win over eighth seed Wesley Moodie.
Auckland is the current British number 14
Auckland, 26, saw off the South African in two tie-breaks 7-6 (7-3) 7-6 (7-5) to reach the quarter-finals in India.
He beat Frank Moser in the first round after two qualifying wins to secure his first-ever ATP Tour singles victory.
Auckland is also through to the doubles second round with fellow Briton Jamie Delgado after a 6-3 5-7 10-8 win over Stefano Galvani and Davide Sanguinetti.
His next singles opponent will be Russian fourth seed Dmitry Tursunov who beat Denmark's Kristian Pless 6-7 6-3 6-4.
Spanish top seed Tommy Robredo and second seed Mario Ancic of Croatia also moved into the quarter-finals.
Robredo recovered from a first-set loss to overcome 115th-ranked Michael Berrer of Germany 5-7 6-2 6-4.
Ancic had less trouble in beating Italy's Stefano Galvani 6-1 7-6 (8-6), but both he and Robredo complained about the humid conditions.
"They aren't easy to handle," said Robredo on a day when the humidity in Mumbai was measured at 70%.
Ancic said: "I felt in good shape, but the humidity is making things very tough."