As one of the finest players of his generation, Cristiano Ronaldo usually gets the better of his opponents on match day.
However, every player has that one opponent they struggle to play against every time they meet and, as it turns out, multi-time Ballon d'Or winners are no different.
Speaking in an interview with Coach magazine, via 101 Great Goals, Ronaldo has revealed the toughest player he has ever competed against and, perhaps to the surprise of some fans, he has plumped for an Englishman.
Ronaldo's career spans Portugal, England and Spain, as well as more than 134 games in the UEFA Champions League and numerous appearances for Portugal in World Cup and European Championships.
As such, the Real Madrid star has a whole host of defenders to choose from when it comes to picking the one he has found most difficult to overcome. The man he ended up choosing? Former Chelsea and England left-back Ashley Cole.
And the reason why...
"Over the years I had some great battles with Ashley Cole," Ronaldo explained. "He doesn’t give you a second to breathe.
"He was such a tenacious player, quick, tough in the tackle – when he was at his peak. You knew it would never be an easy game."
In his prime, Cole was one of the finest left-backs in the world. Known for his pace and ability to attack and defend in equal measure, the Englishman was a nightmare for opposition wingers.
And, while Ronaldo may now more regularly play through the middle, it was on the wing where he began his career, and where he regularly met Cole during his United days.
The Portuguese star's early years at Old Trafford - when he was still learning the game and nurturing his talent - coincided with Cole's prime years at Arsenal and Chelsea so you can understand why the current Los Angeles Galaxy defender is top of the list.
However, perhaps Cole's best performances against Ronaldo came not in the Premier League or Champions League, but on international duty.
The former Chelsea star contained Ronaldo's ever-present threat in England vs Portugal clashes at consecutive tournaments - at Euro 2004 and then again at the 2006 World Cup - and drew much praise on both occasions.
Indeed, speaking after the 2006 contest, Steven Gerrard summed up Cole's ability to handle Ronaldo.
"He had him in his pocket. There aren't too many defenders who can say they've ever done that."