Japanese qualifier Go Soeda shocked Croatia's fifth seed Ivan Dodig 7-6(6), 6-3 in the men's singles second round of the Aircel Chennai Open 2012 on Wednesday.
Soeda needed an hour and 47 minutes to send Dodig packing from the tournament.
Dodig took a medical time-out in the second game of the second set, having his left thigh massaged.
In a match that saw a predominance of baseline play, Soeda, held his nerve to topple the world number 36, who had survived a scare from India's Vishnu Vardhan in the first round.
Dodig was also unhappy with some of the line calls made and argued with the chair umpire and applauded him sarcastically following an explanation.
In the quarter-finals, Soeda will meet defending champion Stanislas Wawrinka of Switzerland, who himself survived a scare from lucky loser Edouard Roger-Vasselin in his second round match.
Earlier in the day, Israeli star Dudi Sela booked a quarter-final match up with Canadian sensation Milos Raonic after outlasting Frenchman Benoit Paire in a match that lasted more than two hours.
Sela won 4-6, 6-2, 6-4 after he hung in and capitalised on Paire's many mistakes, which included many double faults and wasted break-points.