was seen wearing a fuchsia nasal strip during a training session ahead of his ATP Finals opener against Casper Ruud. The four-time Grand Slam champion is said to have a blocked nose and has been attempting to improve his breathing while practising.

Alcaraz has enjoyed a sensational season on the court and bagged another two Majors after cruising to the French Open and Wimbledon titles.

And he will be aiming to finish his season off in style at the showpiece event in Turin this week.

Alcaraz has been at the ATP Finals alongside Ruud, Alexander Zverev and Andrey Rublev and will get his campaign up and running this afternoon. But there could be concerns over his fitness following his training session on Saturday.

The 21-year-old took to the practice court alongside ATP Finals rival Taylor Fritz, with the duo playing one set and one game before their allotted time ran out. And Alcaraz wore the nasal strip for around an hour after he was given it by his physio Juanjo Moreno.

Nasal strips are placed on the bridge of the nose to dilate the nostrils. They make it easier for air to pass in and out, meaning Alcaraz's breathing may well have been improved as he battled with his blocked nose.

Alcaraz will be desperate to clinch ATP Finals glory for the first time after being beaten by eventual champion Novak Djokovic in straight sets in the semi-finals last year.

His biggest rival could be Italian ace Jannik Sinner, who is the favourite to win the event on home soil after landing the Australian Open and US Open titles on the same hard surface. But Zverev, Fritz and Daniil Medvedev will also be eyeing silverware.

And ahead of the tournament, Alcaraz told : "Last year was a difficult end of the year for me. I could not play at my best.

"The last two matches here were pretty good matches for me, but the previous two, three tournaments I didn't play at my best, so I realized I had to change a little bit at this time of the year, which I did this year.

"I come here a little bit different. I approach this tournament a little differently, knowing there are things I have to change if I am to have a good result here and go far.

"Last year I didn't start well from the first matches. I will try to play the same level and will try to play good tennis. "I am coming here with a lot of motivation."