Signing a 36-year-old for £12.9m and paying him almost £5000,000-per-week for two years doesn’t seem like good business.
But Cristiano Ronaldo is no 36-year-old.
To say the Portuguese superstar looks after himself would be an understatement.
Ronaldo is still in sensational nick, possessing a physique that most footballers in their prime can only dream of.
Nobody would be surprised if he’s still playing at the very highest level at the age of 40.
Since re-signing for Manchester United, Ronaldo has already shown that he’s still got it. He’s scored three times in two matches against Newcastle and Young Boys.
While he’s still capable of scoring at a ridiculous rate, Ronaldo’s pace has naturally waned with his advancing years.
At his peak, Ronaldo was one of the fastest players in world football.
These days, he’s transformed himself into more of a poacher, rather than someone who is sprinting around for 90 minutes.
Can you answer these 12 questions about Cristiano Ronaldo's first spell at Manchester United?
But we want to remember when Ronaldo was outrageously quick.
Ten years ago, he took part in a documentary called 'Cristiano Ronaldo: Tested to the Limit'. This featured Ronaldo, who was 26 at the time, taking part in a series of tests.
One of the tests included racing a professional sprinter, Angel David Rodriguez.
Ronaldo vs a professional sprinter. Who would win?
Well, over 25 metres, Rodriguez managed 3.31 seconds, while Ronaldo did 25m in 3.61 seconds.
But Ronaldo had an opportunity to get his revenge.
They were then challenged to a slalom race in between some poles.
There was only going to be one winner on this occasion as Ronaldo completed the course in 6.35 seconds, while Rodriguez took 6.86 seconds.
Video: Ronaldo vs professional sprinter
Rodriguez admitted he was impressed by Ronaldo’s technique and predicted he could run 100 metres in 11.6 seconds.
"I was doing a report on race technique with Cristiano Ronaldo. You had to run in various styles to demonstrate differences in race technique between a sprinter and a footballer," he recalled.
“He is fast and very good at lateral movements. He clearly trains a lot.
“This was the trap they set for me, to start running diagonally. It’s like making a sprinter play paddle tennis.
"I took three tenths from him, which is quite a lot. If it was 100 metres, he may be able to get 11.60 seconds.”