MELBOURNE : Jannik Sinner outlasted Marton Fucsovics 4-6 4-6 6-1 6-2 6-0 to reach the Australian Open fourth round on Friday while Barbora Krejcikova made swift progress after organisers defended their schedule at the Grand Slam over the previous day's late finish.Former French Open winner Krejcikova, a quarter-finalist at Melbourne Park in 2022, went through with a 6-2 6-3 victory over Anhelina Kalinina to remain on course for a potential meeting with American third seed Jessica Pegula.But the 21-year-old Sinner was made to work harder after making a poor start to his match as he dropped his serve twice and made 18 unforced errors to lose the opening set.A neat passing shot at the net after powerful exchanges from the baseline helped Fucsovics break for a 2-1 lead in the second set and the world number 78 heaped more pressure on his opponent by going two sets up before Sinner switched gears.Italian Sinner, the 15th seed who has reached the quarter-finals of all four Grand Slams but has never gone any further, dropped only three games en route to the next two sets playing superior tennis against a fading Fucsovics.He went on to blank his opponent to draw huge cheers from the crowd on Margaret Court Arena, which had witnessed an epic comeback from Andy Murray only hours earlier.The former world number one was not happy to end his match at 4.05 am on Friday, describing the late finish as a "joke" and "disrespectful."Tournament director Craig Tiley ruled out any immediate changes after Murray said tennis must aim to avoid late finishes having completed a remarkable 4-6 6-7(4) 7-6(5) 6-3 7-5 win over Thanasi Kokkinakis."At this point there's no need to change the schedule," Tiley, who has had to negotiate delays caused by