Novak Djokovic was amazed to see Roger Federer save seven match points against Tennys Sandgren at the age of 38.
The Serbian, who will meet Federer on Thursday in the Australian Open semi-finals, marvelled at Federer's ability to stay alive in the competition and feels it proves his greatness.
Djokovic defeated Milos Raonic 6-4 6-3 7-6 (7-1) in a routine quarter-final victory, while Federer's path in a 6-3 2-6 2-6 7-6 (10-8) 6-3 win was something out of the ordinary.
"What he did today was really amazing," said Djokovic. "He showed me he's one of the best players of all time.
"I mean, to come back and save seven match points at his age, he's still playing such a great tennis and proving that he deserves to be up there.
"He never gives up. When it matters the most, he's focused and he plays his best tennis. Sandgren had chances. Out of those seven match points, there were five match points where they actually had rallies.
"But credit to Roger. Amazing that he managed to come back. It's not the first time he has done that in his career. That's why he is who he is."
It was pointed out to Djokovic that he had saved six match points in his career against Federer, four across two appearances at the US Open and two in their famous Wimbledon final last year.
But he insisted he could not compare whether that feat was more surprising than the Swiss star surviving seven in the same match on Tuesday.
"I don't know, I can't compare it," he said. "I hope I get to at least one match point in a few days!
"Obviously I have tremendous respect for Roger and everything he has achieved in the sport, definitely one of my two biggest rivals. He's a great fighter.
"I have been saying many times and I'll repeat it again: the matchups against Roger and Rafa [Nadal] have made me the player I am today so I am grateful I have had so many great matches against those guys.
"Hopefully things can come together for me in a positive way on Thursday and I can have a chance to win."
The numbers back Djoker
The Serb insisted he does not feel like he is "dominating" Federer despite not losing a grand slam match against the Swiss in seven and a half years. Federer has not defeated Djokovic at a major since their Wimbledon semi-final meeting in 2012.
Despite five grand slam wins over Federer since then, four of which have arrived in finals, the Serbian does not feel like he has the upper hand ahead of their meeting on Thursday.
Djokovic insisted the 38-year-old, who won their previous meeting at the 2019 ATP Finals in London, always remains a huge threat on all surfaces.
Asked if he knew the reason for his winning streak against Federer at the majors, he said: "Not particularly, to be honest.
"Wimbledon last year, he had two match points, he was one shot away from winning that match. It's not like I've been dominating the match-ups.
"I've had success against him in grand slams in particular. But Roger is Roger. You know that he's always going to play on such a high level, regardless of the surface.
"He loves to play these kind of matches, big rivalries, semis, finals of grand slams.
"I mean, he's probably going to confirm that that's probably the biggest reason why he's still competing, to be able to compete at the grand slams against the best players in the world."
Since dropping a set in the first round against Jan-Lennard Struff, Djokovic has recorded four consecutive straight-sets victories, including Tuesday's 6-4 6-3 7-6 (7-1) quarter-final triumph over Milos Raonic.
The run has followed his star showing at the ATP Cup, where he led his country to victory and beat Rafael Nadal in the final.
Djokovic is in a confident mood ahead of the match with Federer as he sits two wins away from a record eighth Australian Open title.
The second seed said: "I've been feeling well on the court. If I continue playing the way I was throughout the tournament here and also ATP Cup, I've been building.
"I think as the time passes by, in every match, I have more confidence, I feel better.
"In the end of the day, this is the court where I had the most success in my career."
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