Juventus coach Massimiliano Allegri insists Cristiano Ronaldo is "serene" despite a warrant for his DNA amid the ongoing investigation into a rape allegation.

American Kathryn Mayorga has accused Ronaldo of sexually assaulting her in a hotel in Las Vegas in 2009, something the Portugal captain has strenuously refuted.

German publication Der Spiegel first reported the claims, which also included the suggestion Ronaldo paid Ms Mayorga $375,000 in 2010 as part of a privacy agreement, preventing her from going public with the allegations. Ms Mayorga filed a lawsuit in an attempt to quash that agreement, while Las Vegas police have re-opened an investigation.

Ronaldo's lawyer Peter Christiansen confirmed the payment was made to Ms Mayorga, but said some documents presented as evidence had been "stolen" and "completely fabricated", while the Juventus forward described rape as an "abominable crime" in an October statement he issued to "firmly deny" the accusations.

The Wall Street Journal reported on Thursday that Las Vegas police had requested a sample of Ronaldo's DNA, and after Christiansen insisted this was a "very standard request", Allegri believes his key player is calm.

"It's his personal question, I talk about football," Allegri told reporters ahead of Saturday's Coppa Italia clash with Bologna.

"I can tell you that I saw him very serene, he is training well. It has been a very tight four months, now we need to work to play better in the 36 potential games we have left.

"I see Cristiano peaceful and calm, I go on that. For the rest, it is not for me to answer because they are private affairs."

Saturday's trip to Bologna is Juve's first game back after the mid-season break and it was put to Allegri that he might opt to carefully "manage" Ronaldo's playing time in the second half of the campaign.

Two days to go before Bologna tie 

"Until now, he has never gone to the national team [while at Juve]," Allegri said. "The six games that he spared with Portugal he has then played them in the league with us, so he played more or less the same matches last year.

"As we move forward, I will manage the condition of all in order to try to arrive at the end of all the objectives well. He [Ronaldo] will play on Saturday, but let's see how and when."