Channel Seven commentator Bruce McAvaney picked it early in the second set. "Some strange things are happening out here today," McAvaney observed.
It was succinct, but it was spot on. Milos Raonic and Stan Wawrinka had met once in each year since 2012. Until Monday, Wawrinka had claimed each of their annual contests. But having lost eight consecutive sets against the fourth-seeded Swiss, Raonic claimed three of five on Monday, enough to eliminate the dual major champion from this year's Australian Open.
With his 6-4, 6-3, 5-7, 4-6, 6-3 win in three hours and 45 minutes, the Canadian 13th seed set up a Wednesday meeting with 23rd seed Gael Monfils, and a chance to make his second semi-final at a grand slam event. 
Both Wawrinka and Raonic entered the match unbeaten in 2016, and having not dropped a set so far at the tournament.
But with the beauty of hindsight, circumstances had favoured the big-serving Canuck. Wawrinka, champion here two years ago, conceded he had struggled with illness during his win on Saturday against Czech Lukas Rosol. On the same day Raonic had dismantled Serbian 21st seed Victor Troicki.
Only one break point came the way of either Wawrinka or Raonic in the first set, but that chance at 30-40 in the ninth game of the match was the only opportunity the underdog needed.
Things looked like they may have turned in the second game of the second set. Receiving a second serve at 30-40, Wawrinka licked up the 156km/h relative treacle delivered from the Canadian's racquet. But just as quickly Raonic broke back, with all four of his points coming from unforced errors. Stan was sluggish, and Raonic - his serve-and-volley game on song - was happy to pounce.
Wawrinka had an opening as Raonic tensed up late in the the 11th game, typified by a volley he let go at 15-15, one which landed in his backcourt, a winner for the Swiss. Raonic saved a pair of break points with 219km/h and 223km/h first serves, but Wawrinka capitalised after seeing a second serve on the third. With an upswing of momentum he took the set.
Raonic had for the most part exuded calmness, his newly utilised stress-relieving mouthguard appearing to do its job, with Wawrinka gesticulating frequently. But paradoxically, the more Raonic approached the net, the more Wawrinka encroached on the scoreboard. The Swiss broke in the fifth game of the set, his backhand swinging into gear. Then, having missed four chances to break back in the eighth game, the emotions at last flowed out of Raonic. A wry smile, a groan, a frustrated swat - parts of his arsenal unseen to that stage - emerged. He couldn't close the gap, and Wawrinka took it to five.
It looked as though Raonic might be forced to settle with the sentiments of Samuel Beckett - tattooed on his opponent's forearm - a better failure.
But after a closely fought opening to the decider Raonic claimed his second break point of the sixth game, and unleashed a guttural roar. Calling on the "calm" he said after the match had been brought by new coach Carlos Moya, Raonic served it out. It was his first win on Rod Laver Arena, making it a strange but marvellous day.