Alex De Minaur has raised alarm bells ahead of his US Open quarter-final clash with Jack Draper. The pair will face off in the second day session match on Arthur Ashe Stadium today (Wednesday).

Ahead of their showdown, 10th seed De Minaur practised for just 15 minutes before walking off court looking like "the most dejected and de-energised player".

Earlier this summer, the Aussie was forced to pull out ahead of his Wimbledon quarter-final against Novak Djokovic when he injured his hip. The US Open is the first singles tournament he has played since.

Ahead of his maiden Grand Slam quarter-final, Draper enjoyed a productive practice session. But it was a different story when his opponent took to Arthur Ashe for a pre-match hit.

On Sky Sports, Karthi Gnanasegaram and Annabel Croft revealed that De Minaur left the court after just 15 minutes, leaving them standing in front of an abandoned court. "You may also notice that we have an empty court behind us. Alex De Minaur came out here at 11 o’clock New York time, practised for about 15 minutes and has left," Gnanasegaram said.

And the shots he hit during his 15 minutes on court concerned Annabel Croft, who claimed that he looked "dejected" when he left. The retired British tennis player explained: "It couldn’t have been more of a contrast to Jack Draper’s practice session.

"I don’t think I’ve ever seen a warm-up that short and I’m going to be honest with you, we were talking about how energised and aggressive Jack Draper was looking.

"I felt like De Minaur looked as if he didn’t really want to move his feet, was either trying to converse energy or he was just feeling very lethargic out there. He hardly did any groundstrokes from the back of the court, walked up to the net, did a few volleys, did about five minutes of each."

Croft was mostly alarmed by De Minaur's attempts to work on his serve. She continued: "I’ve not really seen players go up to a serve after 10 minutes of a warm-up for such a big match. And then he did quite a few, well I say, the serves didn’t register on the clock so they were very lethargic serves."

"Then he started to step it up a bit but the only serves he did on the deuce serve were to the forehand down the middle which was quite interesting. Then he moved across to the ad side. Again, he went down the middle, so as if he was going to serve to Jack Draper’s backhand, and then at the very end of the warm-up he served a few out wide to the forehand."

The world No. 10 quickly cut his session short and didn't look convincing when he left. "He was trying to hit a few winners off the very next serve and then he just put a thumbs up and it was like, practice over, picked up his water bottle," Croft added.

"If you were going to judge the practice, he’s definitely won the practice match today. But after he picked up his water bottle, he sort of sloped off court looking the most dejected and de-energised player who is about to play a massive match against Jack Draper. So read into that what you like, but it wasn’t a great practice."

But former British tennis stars Laura Robson and Tim Henman didn't want to jump the gun too many assumptions about the 25-year-old's physical state. "It was 15 minutes. He was hitting his serves at the end, didn’t really look like he was going after it with his shoulder, I don’t know," Henman said, reacting to the talk of his practice session.

Robson interjected: "But you wouldn’t really go all out anyway, would you?" Henman replied: "You’d be hitting them harder than that to get your rhythm and get loosened up.