Sir Alex Ferguson believes Cristiano Ronaldo is a better player now than he was during his time at Manchester United.
Ronaldo, 28, spent six successful years at Old Trafford, during which he scored 117 in 290 appearances, including 42 goals in 2007-08 as United won the Premier League and Champions League.
On Wednesday, four years after leaving Manchester to join Real Madrid for a world record £80m, the Portugal international will line up against his former club, looking to add to his tally of 182 goals in 179 games for the Spanish club.
"Cristiano is a better player than when he left us because of his maturity," said Ferguson. "He is at the peak of his career now.
"He was still a young man when he left and you can see how he has flourished in Madrid. His fitness, speed, goals - and he's never injured. That is unique in the modern game.
"I never thought he'd get the amount of goals he's scored. I knew he'd improve. I knew he was one of the best players in the world. But to score the goals he has is phenomenal."
However, United have their own attacking threats.
The major difference for United in the title race this term has been the arrival of Robin van Persie, who on Sunday took his goals tally for the season to 23 against Everton.
"Robin is now approaching that level," said Ferguson of comparisons with Barcelona's Lionel Messi and Ronaldo. "He has been a breath of fresh air."
Van Persie's strike-partner Wayne Rooney was depicted as a "hooligan" in the Spanish press on Tuesday, with sports daily Marca also describing the England player as "a freckled demon" who is "built like a barrel packed with gunpowder" and on his way to "blow up the Bernabeu".
"He is a mature player now," said Ferguson of Rooney. "He is 27. When players mature little bits of their games change.
"His goalscoring has been very consistent. He used to score in snatches. Now there is a far more consistent nature to his goals.
"He also plays different positions with great enthusiasm. Not every player in the world has these qualities."
Asked about today's unflattering reports in the Spanish press, Ferguson said: "Rooney can't read Spanish so we will be all right."