Novak Djokovic admits fitness concerns ahead of US Open clash with Carlos Alcaraz

The 24-time Grand Slam has struggled with several niggles â- from blisters to a back injury to a shoulder problem â- so far at the hard-court major, but he is safely into the last four after he maintained his unblemished record against Fritz.

Djokovic increased his lead in their head-to-head rivalry to 11-0, but he did drop a set against the American before winning 6-3, 7-5, 4-6, 6-4.

Aged 38, the former world No 1 would have loved to wrap it up in three sets, but he acknowledged that Fritz was the better player for most of the second and third sets and, in the end, he was happy to get the win.

"It was an incredibly close match. It was really anybody's match. I thought I was lucky to really save crucial breakpoints in the second set," the four-time US Open champion said.

"For most of the second and third set he was the better player. In these kinds of matches, few points decide the winner. It was fortunately coming on my side, particularly at the end of the fourth set."

He will return to action on Friday for the semi-final against Alcaraz in what will be their ninth career meeting. The veteran leads their H2H 5-3 with his two most recent wins coming at this year's Australian Open and the gold medal match of the 2024 Paris Olympics last August.

Djokovic, though, is starting to feel his age.

"Good thing about the schedule is now that I have two days without a match, so that helps a lot," he said. "So I don't feel very fresh at the moment. But hopefully in two days will be different.

The seventh seed added: "It's not going to get easier, I tell you that. But look, as I said, I'm going to try to take one day at a time, really take care of my body, try to relax and recover.

"The next couple of days is really key for me to really get my body in shape and ready to battle five sets if it's needed. So I just would really love that, would love to be fit enough to play and to play, you know, potentially five sets with Carlos. And I know that my best tennis is going to be required, but I rise to the occasion.

"Normally, I like to play the big matches on a big stage. It's just that I'm not really sure how the body is going to feel in the next few days. But, you know, I'm going to do my very best with my team to be fit for that. There's going to be a lot of running involved, that's for sure. I mean, there's not going to be short points."

Alcaraz and defending US Open champion Jannik Sinner were the two pre-tournament favourites and many believe they will meet in the final at Flushing Meadows. Should the form book hold, it will be their third consecutive Grand Slam final as Alcaraz won their showpiece match at Roland Garros before Sinner turned the tables at Wimbledon.

Djokovic, though, wants to spoil the party.

"We don't need to spend words about two of them. You know, we know that they're two best players in the world," he said.

"Everybody's probably expecting and anticipating the finals between two of them. I'm going to try to, you know, mess up the plans of most of the people and let's see, you know, Sinner still has to win a couple of matches to get to the finals, but they are playing definitely the best tennis of any player here.

"They've been the dominant force since the beginning of the tournament, but, you know, I definitely am not going with the white flag on the court. I don't think anybody does, really, when they play them, but particularly not me.

"I put myself in another semi-final of a Grand Slam this year. I've been very consistent, mostly consistent on the Slams this season, and that's what I said at the beginning of the year, where I would like to perform my best tennis and make the best results."

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