Why have there barely been any upsets at this year’s Australian Open so far? That’s the big question for David, Catherine and Grad Matt on The Tennis Podcast after another day which saw the top seeds progress.There were shocks brewing in the morning as both Naomi Osaka and Elina Svitolina found themselves a set down. How did they pull through?Later in the day, Serena Williams and Simona Halep both won to set up their blockbuster Last 16 match. What was Halep like when she spoke to Catherine afterwards? And how is she getting on without a coach?In the men’s draw, Novak Djokovic beat Denis Shapovalov easily. But what caused his third set wobble? And are we right to be a bit disappointed in Shapovalov’s performance?Looking ahead to Day 7, why does David have a sneaky feeling that Stefanos Tsitsipas might beat Roger Federer?The Tennis Podcast will be produced daily throughout the Australian Open (and at all the Slams) after our Kickstarter was funded by our listeners. It is produced in association with The Telegraph. See acast.com/privacy for privacy and opt-out information.