Ander Herrera has praised Zlatan Ibrahimovic's influence over the Manchester United squad.
The former Sweden international signed for the Red Devils on a free transfer during the summer after spending four years at Paris Saint-Germain.
The 35-year-old has made an early impression in the Premier League having scored four goals, and Herrera has claimed that the striker is just as dedicated in training as he is on matchday.
"He's unbelievable," Herrera told the club's official website. "He doesn't lose one training session. He trains every day at his best trying to get everyone at their highest level.
"He is very, very aggressive and demanding but in a good way because every day he wants to win every training session and he wants everyone with him to win to keep working so we are very lucky to have Zlatan with us.
"If you see a game and you didn't know Zlatan's age you could think he was only 28 or 29 and that is good for us."
Meanwhile, Herrera has received his first call-up to the Spain senior squad.
