Asked afterwards if he felt differently from previous years and believes this could finally be his year, the 24-year-old Tsitsipas said, “I’m feeling great with my tennis. I don’t think I felt so good in a long time.
“I will definitely say yes to it. I’ve said it, I’m a different player, playing different. My mentality is different.
“When I’m out on the court, I don’t really think of negatives, to be honest. I just go out there and play the game.”
Tsitsipas, who will become world number one should he win the title, has thrived on the energy from the crowd in Melbourne.
The city has a large Greek population, including some of his extended family, and he considers this his “home” tournament.
Tsitsipas’s best Slam so far is reaching the French Open final in 2021, falling to Novak Djokovic in five sets after holding a 2-0 lead.
Lehecka, ranked 71, warned before the match he wanted revenge after losing to Tsitsipas in the semi-finals at Rotterdam last year.
But the 21-year-old, who beat 11th seed Cameron Norrie and sixth seed Felix Auger-Aliassime en route to the last eight, was immediately under the gun.
Tsitsipas worked five break points on his opening service game and got over the line when the Czech smacked a backhand volley wide.
He consolidated for a 3-0 lead and with his strong first serve offering Lehecka few opportunities to strike back, coasted to the first set in 36 minutes, sealing it with an ace.
Tsitsipas saved five break points to hold in a crucial third game of the second set as Lehecka came alive and began applying pressure.
Both players dug in and it went with serve to a tiebreak, where the Greek kept his cool to take an early advantage that he never gave up.
In a close third set, Tsitsipas second double fault of the night handed Lehecka three break points in game seven.
But he saved them all to hold, pumping the air in celebration.
With the bit between his teeth, the Greek star dialled up the pressure as Lehecka served to stay in the contest and a crosscourt backhand earned him a match point which he converted.
“It felt different this time from any other match and the most important thing in the end is that I found a solution,” said Tsitsipas.
To make his first final in Melbourne, Tsitsipas will have to get past Khachanov.
The Russian is into his second straight Grand Slam semi after a run to the same stage at last September’s US Open.
“I think the first semi-finals which I did in US Open, that gave me an extra boost and extra confidence to show where I really am, what I can do when I’m at my best,” said Khachanov.
“Physically also, after pre-season, I’m feeling really good so far.”