Aussies Jason Kubler and Chris O'Connell have both made it through to the second round of the Qatar Open, but in contrasting fashions.
Kubler was given a helping hand when Russia's Aslan Karatsev retired on Monday afternoon at the Khalifa International Tennis and Squash Complex in Doha.
The 29-year-old Queenslander, ranked No.74, was ahead 7-6 (7-4) 1-0 when Karatsev, the world No.101, pulled out.
Karatsev gave up the first set tie-break with a double fault and retired after just one game of the second set.
Kubler has already enjoyed success in doubles this year, winning the Australian Open doubles last month alongside Rinky Hijikata, when they beat Hugo Nys and Jan Zielinski.
The Australian will face Canadian No.2 seed Felix Auger-Aliassime next.
O'Connell, ranked No.94, followed Kubler on court and beat the veteran Spaniard Fernando Verdasco 6-1 3-6 6-0.
Sydneysider O'Connell will play the winner of Tuesday's match between Spaniard Roberto Bautista Agut, the No. 5 seed, and Hungary's Marton Fucsovics in the last 16.
