Melbourne: Andy Murray breezed into quarter-finals of the Australian Open Monday after Mikhail Kukushkin retired due to injury in their third set.
Murray, who had toiled against the Kazakh in the Brisbane warm-up tournament, was leading 6-1, 6-1, 1-0 when Kukushkin said he could not continue due to a hip flexor injury, allowing the Briton to retreat from the scorching heat on Rod Laver Arena.
World number four Murray, the runner-up at Melbourne Park for the last two years, will next play Jo-Wilfried Tsonga of France or Japan`s Kei Nishikori.
Murray paid tribute to his new coach Ivan Lendl who watched from the stands, saying the eight-times grand slam champion had given him a welcome shot of belief in the leadup to the year`s first grand slam.
"The mental side is huge in tennis, something that I`ve tried to get better at over the last few years ... I feel more comfortable this year," Murray said in a courtside interview.
"I don`t know if you know but in the UK we haven`t won a grand slam in 100 years," he quipped with interviewer and former world number one Jim Courier.
"It`s something that I`ve just got to deal with, I`ve got better at it in the last few years."