Jannik Sinner was featured in fellow Italian star Matteo Berrettini's latest video from his Vienna dump, and it had the World No. 2 talking about his hair routine. Sinner has blonde hair and is kind of "messy."In the video, Berrettini asks Sinner about his hair routine, wanting to know what he puts in his hair. The 2025 Wimbledon replied that sometimes he doesn't even use shampoo. Berrettini further asked if Sinner washes his hair, to which the World No. 2 said:"Depends. It depends on the day"Berrettini was perplexed and jokingly replied:"You’re lucky you don’t stink. Bravo."Jannik’s hair routine byu/Forward_Number_24 intennisMatteo Berrettini and Jannik Sinner both featured in the Vienna Open. Berrettini was defeated in straight sets by Alex de Minaur in the quarterfinal. Meanwhile, Jannik Sinner advanced to the final after defeating de Minaur in straight sets in the semifinal. The Italian is preparing for the final against Germany's Alexander Zverev.Jannik Sinner withdraws from Davis CupIt has been a long season for Jannik Sinner, winning several titles, including two Grand Slams. With the season coming to an end after the ATP Finals in Turin, the Italian made a controversial decision.He announced that he will be skipping this year's Davis Cup Finals scheduled in Bologna, Italy, from November 18 to 23. Sinner cited the need to rest and recover so he can give his best at the Australian Open in January."It wasn't an easy decision, but after Turin [where the ATP Finals are played the week before the Davis Cup], the goal is to start off on the right foot in Australia," Sinner said via ESPN."It doesn't seem like it, but a week of preparation in that period can make a difference. We already won the Davis Cup in 2023 and 2024 and this time we decided like this with my team."The decision hasn't gone down well with the Italian media, who criticized the tennis star for featuring in the cash-rich Six Kings Slam, where he bagged $6 million upon winning the tournament, over turning up for national duties. Gazzetta dello Sport's editorial said:"So you're not going to return to Riyadh for another $6 million? If you win another Wimbledon, you won't go to London anymore? Pasta, coffee ... Every five minutes you promote an Italian product. Do it with tennis, too."Sinner's decision puts Italy in a tough spot, as they were hoping for the presence of World No. 2. It remains to be seen if Sinner decides to walk back on his decision.