Novak Djokovic feels he has "something extra" at this year's Australian Open as he prepares to do battle for a place in the Melbourne final.
Nine-time champion Djokovic hopes to reach a 10th final at Melbourne Park when he takes on American Tommy Paul in the last four on Friday.
For Paul, it marks a maiden Grand Slam semi-final, in which he will face Djokovic for the first time.
Earlier in the day, third seed Stefanos Tsitsipas will meet Karen Khachanov.
Greece's Tsitsipas is chasing a place in his second major final when he takes on Khachanov on Rod Laver Arena from 03:30 GMT, while his Russian opponent has never progressed from a Grand Slam semi-final.
Fourth seed Djokovic and Paul will go head to head from 08:30.
Elsewhere, Britain's Alfie Hewett and Gordon Reid chase a fourth successive wheelchair doubles title when they take on Dutch duo Maikel Scheffers and Ruben Spaargaren in the final.
Fellow Briton Ranah Stoiber is also in action in the junior girls' singles semi-finals.
Djokovic 'couldn't ask for a better situation'
A lot can happen in 12 months. One year ago, Serbia's Djokovic was absent from the Australian Open having been deported from the country because of his Covid-19 vaccine status.
Move the clock forward to the present day and he is playing some of his finest tennis, a hamstring injury no longer hampering him the way it did in the early rounds of the tournament.
"I always try to give my best, particularly in Grand Slams, because at this stage of my career those are the tournaments that count the most," said the 35-year-old.
"But you could say that there is something extra this year, yeah. You could say because the injury, what happened last year. I just wanted to really do well.
"So far I have a perfect score in Australian hard courts, in Adelaide and here. I've been playing better and better. I couldn't ask for a better situation to be in at the moment."Novak Djokovic is bidding to reach his 33rd Grand Slam final
Djokovic has never lost a semi-final at Melbourne Park, and indeed never been defeated in the Australian Open final.
He is favourite to be crowned champion once again - a feat that would draw him level with men's record holder Rafael Nadal on 22 Grand Slam titles.
Djokovic reached the last four with clinical straight-set wins over Alex de Minaur and Andrey Rublev in the previous two rounds.
"Playing against two guys that are really good players, in-form players, to beat them dominantly in three sets, is definitely something that I want in this moment, something that sends a message to all my opponents remaining in the draw," said Djokovic.
"With this kind of game, of course the confidence level rises. I feel good on the court, better and better as the tournament progresses. I've been in this situation so many times in my life, in my career, never lost a semi-finals in [the] Australian Open. Hopefully that will stay the same."
Standing in his way is 25-year-old Paul, who despite having never gone past the fourth round of a Slam before this tournament, is unperturbed about facing Djokovic for the first time.
"It's going to be a challenging match. But I'm playing some of my best tennis, so it's a good time," he said.
Paul is the first American to reach the semi-finals in Melbourne since Andy Roddick in 2009, and should he win, would be the first player from his country to make the men's final since Andre Agassi in 2003.
He is one of 10 American men who will be in the world's top 50 at the end of the Australian Open.
"That's all we've been hearing, since like 14 years old," said Paul. "The coaches have been telling us, 'We need new Americans, we need new Americans'. It's kind of engraved in my head.
"We all want to perform. Obviously Frances [Tiafoe] was pretty damn close at US Open to getting past the semis. Who knows what would have happened in the finals? I think we all want it pretty bad for ourselves, but we want it for US tennis, too."
Tsitsipas 'very hungry' before facing KhachanovKaren Khachanov and Stefanos Tsitsipas are both seeking a maiden Grand Slam title
Tsitsipas, at number four, is the highest ranked player left in the draw and has now reached the Australian Open semi-finals in four of the past five years.
The 24-year-old, who says the tournament feels like his "home" major, has won four out of his five matches so far in straight sets and credits a change of mindset.
"There is this one sort of way of looking at tennis that you're really exhausted after every match," he said. "Every single thing you try to do on the court takes a lot of effort.
"There's this other version of tennis where you're doing your job but you're enjoying it so much you don't care if it's exhausting or not. You're refreshed by it every single time.
"I think I'm heading towards more of that lately than the other thing. I'm very happy to be out on the court. I'm very happy to be performing. I'm very happy to hit some good shots.
"It's just this whole dynamic that has made me very hungry and has created a lot of desire for me to be playing tennis, wanting to achieve new things."
Tsitsipas has won all five of their previous meetings. This will be their first a Grand Slam.
US Open semi-finalist Khachanov should be the fresher of the two in the semi-final, a fourth-round win wrapped up in three sets before having his quarter-final cut short when opponent Sebastian Korda retired through injury.
The world number 20 is in new territory in Australia, having never previously navigated past the third round.
"This time it's different because I'm physically also, after pre-season, feeling really good so far," he said.
"I haven't had long matches, so it's different, it can be three also in the semis. But coming into it I'll be in physically better shape."