Murray built a huge lead, let it disappear completely, then needed to save a match point against Matteo Berrettini — who is nearly a full decade younger and ranked more than 50 places higher — before managing to pull out a 6-3, 6-3, 4-6, 6-7 (7), 7-6 (10-6) triumph in the Australian Open’s first round across more than 4 1/2 hours on Tuesday. This was three-time major champion Murray’s first defeat of a top-20 opponent at a Grand Slam tournament since 2017. That was before Murray thought he would need to retire — and indeed was given a career send-off at Melbourne Park in 2019 when he exited in the first round a year after his first hip operation. But a second surgery inserted a metal hip and Murray decided to try to continue playing. This sort of evening was likely what he had in mind when he pressed on. And what a performance this was, filled with the sort of grit that defined much of Murray’s time on tour, that carried him to championships at the US Open in 2012 and at Wimbledon in 2013 and 2016 and to two Olympic singles gold medals. Murray finished 2016 ranked No. 1, but the Scotsman is now 35 years old and ranked No. 66. Still, there were moments Tuesday when Murray played as he did a long time ago, diving to hit a volley before slamming to the blue court or racing to somehow reach seemingly unreachable shots, then shaking a fist and yelling, “Let’s go! Come on now!” Murray raced through the first two sets in less than 1 1/2 hours before the big-hitting, big-serving Berrettini turned things around and took the match to a fifth, even coming within one point of victory at 5-4 in that set but faltering and flubbing an easy backhand. They played under a closed roof at Rod Laver Arena because of temperatures that soared up to 100 degrees Fahrenheit (38 Celsius) and caused suspensions of play that lasted hours in matches on smaller courts that can't be covered.