Manchester United manager Ole Gunnar Solskjaer believes Red Devils superstar Cristiano Ronaldo can play football into his 40s.
Ronaldo returned to Premier League giants United before the transfer window closed and the evergreen 36-year-old has scored four goals in his first three matches back at the club.
As Ronaldo continues to defy his age, Solskjaer does not anticipate the five-time Ballon d'Or winner slowing down any time soon.
"I wouldn't be surprised if he was still playing at 40, not at all," Solskjaer told reporters ahead of Saturday's clash with Aston Villa.
"The way he looks after himself, that's the key, that's the key to it all and, of course, some genes. There must be some genes in there! He has put every single ounce of energy and effort into becoming the player he is.
"He deserves every single plaudit that he gets for first, his own physical state but, even more impressively, when you have achieved as much as he has. He is still just as hungry as ever.
"His mentality is still absolutely spot on and that's just desire from inside of him and he's going to keep going until his legs or even his head say no that's it, I've given everything now."
United – level with Chelsea and Liverpool atop the Premier League – have won 18 of their last 21 home league games against Villa (D2 L1), failing to score on just one occasion in that run.
In Premier League history, no side has won more games against an opponent than United's 37 victories against Villa.
Since a goalless draw with Manchester City last December, United have scored in each of their last 15 Premier League home games (44 goals in total). However, Solskjaer's men have also conceded in each of their last seven league games at Old Trafford, last having a longer top-flight home run without a clean sheet in February 1972 (8 games).
United are the highest scorers in the Premier League so far this season with 13 goals. With an expected goals total of eight, the Manchester outfit are also overperforming their xG more than any other side this season (five goals more).