Learner Tien, a 19-year-old American qualifier, has outlasted marathon man Daniil Medvedev in an astonishing Australian Open boilover, sending the three-time finalist spinning out of the tournament in an exhausting, early-hours epic.

With the clock ticking towards 3am on Friday, the Californian teen, who’d looked down and out after the fifth seed made one of his trademark comebacks, found remarkable mental and physical reserves to pull off a 6-3 7-6(4) 6-7(8) 1-6 7-6[10-7] triumph in 4 hours 49 minutes at Margaret Court Arena.

A healthy-sized, if bleary-eyed crowd, stayed on, transfixed by the drama as world No.121 Learner – given the memorable name by his maths teacher mum – ended up the teacher, giving a lesson in indefatigability to the out-of-sorts king of the stayers.

“I was definitely hoping it wasn’t going to go a fifth-set breaker,” smiled Tien, who’d only won his first Grand Slam match a couple of days earlier but is now the youngest American man in the third round in Melbourne since 18-year-old Pete Sampras in 1990.

“Either way, just really happy to get a win. I know I made it a lot harder than maybe it could have been … but, whatever!”