Two-time former champion Lleyton Hewitt was knocked out of the ATP Next Generation Adelaide International on Thursday after losing his round-robin encounter with Russia’s Igor Kunitsyn in three sets.
Kunitsyn, who enjoyed a straight-sets win over Martin Vassallo Arguello on Wednesday, lost the first set on Thursday but bounced back to overcome the 1998 and 2000 tournament winner 4-6 7-6 (7/4) 6-4 in seven minutes short of three hours.
The 25-year-old Vladivostok-based player will face Argentinian teenager Juan Martin del Potro in the quarter-finals.
Del Potro, 18, beat eighth-seeded Frenchman Paul-Henri Mathieu 7-6 (7/3) 0-6 6-3 on Thursday to claim his place in the last eight, saving 10 break points en route.
Mathieu’s fellow Frenchman Richard Gasquet did manage to advance to the quarter-finals, but was made to work hard to see off Canada’s Frank Dancevic 7-5 5-7 6-3.
Gasquet will next take on Australian left-hander Chris Guccione, who beat another Frenchman, number six seed Arnaud Clement, 7-6 (7/4) 7-6 (7/5).
Vincent Spadea secured his place in the last eight with his second straight-sets victory of the week, this time 6-1 7-6 (8/6) against Evgeny Korolev of Russia.
The American next faces Joachim Johansson, the Swede having progressed courtesy of a better head-to-head record with Gilles Simon after both finished with 1-1 records.
Simon, the seventh seed from France, was level with compatriot Florent Serra at 6-2 5-7 1-1 when his opponent was forced to retire with an upset stomach on Thursday.