Andy Murray battled past Roger Federer in five sets to reach his third Australian Open and sixth Grand Slam final.
The Briton, seeded third, will face world number one Novak Djokovic in Sunday's final after beating Federer 6-4 6-7 (5-7) 6-3 6-7 (2-7) 6-2.
It required a dramatic four hours on Rod Laver Arena, with Murray dominating for the most part but Federer's brilliance keeping him alive.
The Scot served superbly, firing down 21 aces, only for Federer to dominate the two tie-breaks.
And after failing to serve out the match in the fourth set, it looked as though Murray might have missed his chance when it came down to a fifth.
However, just like he did in winning his first major title at the US Open, Murray rose to the occasion in the deciding set and raced away with it.
"It's always tough against him, when he plays in Slams is when he plays his best tennis," said Murray.
"When his back was against the wall at 6-5 and I was serving, he came up with some unbelievable shots. I just had to keep fighting."
Federer, the four-time champion, said: "Definitely it was more of a chase.
"Obviously you're going to go through a five-setter with some regrets. But overall, I think Andy was a bit better than I was."
Federer had needed five sets to win his quarter-final against Jo-Wilfried Tsonga two days earlier, and he was overpowered in the decider this time.
An early break when Federer framed a backhand was enough as Murray rediscovered the potent serving of the early stages, closing it out when Federer sent a forehand long.
The major concern around Murray before the match was that he had not been tested in five straight-sets wins, but a thumping forehand winner on the second point suggested he was not suffering from a lack of intensity.
Returning superbly, he kept Federer on the back foot from the outset as the Swiss struggled to win any free points on serve.
Murray missed a break point in the opening game and forced another three two games later, grabbing the break with a cross-court forehand at the fifth opportunity.
Federer saw an ace fly past him after fashioning his first chance of the match in game four, and he would not earn another break point until the fourth set.
Murray saw out the opener in 45 minutes and continued to dominate in the second, but Federer at least began to gain a foothold.
The 17-time Grand Slam champion provided enough flashing winners to keep his large following happy and made it to the sanctuary of a tie-break, which he dominated.
Two wayward forehands from Murray gave Federer the perfect start and, after being pegged back to 5-5, the Swiss played a magnificent backhand pass after the Scot failed to put away a smash.
The set was his but the momentum did not shift. Murray slapped a forehand wide on an early chance in the third set but visibly geed himself up after a strong hold at 3-2, and moments later broke to love.
Two more thunderous aces took him to the set and restored the lead his play deserved.
Federer was not done, capitalising on a sloppy game from his opponent to move 4-1 up in the third, but when the Briton came storming back to level and then broke for 6-5, the end appeared imminent.
Murray powered his way to 30-0, two points from victory, with a thumping forehand followed by a snarl of satisfaction, only for Federer to ignite the crowd with a blistering backhand winner as he recovered the break and forced a second tie-break.
Again, Murray started poorly, dazed by his missed opportunity, and Federer raced through it to force a deciding set - the first time in his long career that the Swiss had played back-to-back five-set matches.
Murray might have been expected to crumble, but just as against Djokovic in New York last September, he played a superb final set.
It was Federer who lost his way, framing a backhand under huge pressure to give up the crucial break in game two, and Murray resumed the serving prowess of earlier as he powered towards the finish line.
A forehand down the line brought up match point on the Federer serve, and the Swiss cracked one final time with a mistimed forehand to send Murray back to the Melbourne final for the third time in four years.
"It's big," said Murray. "I never beat Roger in a Slam before. It definitely will help with the confidence. Just knowing you can win against those guys in big matches definitely helps."