Eden Hazard's struggles at Real Madrid have been well-documented, and the challenges faced by the Belgian only serve to emphasise the size of Cristiano Ronaldo's achievements in the Premier League.
Current Chelsea man Saul Niguez has a theory as to why Hazard has found things tough in Spain. pointing to the differences between the Premier League and La Liga, and even Lionel Messi has had a tough time since leaving Barcelona for Paris Saint-Germain.
Ronaldo has had no such issues on a personal level, though, leading the goalscoring charts for Manchester United in his first season back.
The Portugal international is older than Hazard, and had a spell in Italy before returning to the Premier League, but he has shown the transition can be made.
Does Hazard need to follow Ronaldo's example and return to England? Have your say in the comments section
"When he was here, he was easily one of the best players in the world and then he goes to La Liga and has his own difficulties because it’s a totally different game," Saul told the Chelsea website regarding Hazard.
"Here he had more one-vs-ones and two-vs-ones but in La Liga, because everyone knows how good his team is and how good he is, other teams make it much more difficult for him.
"Here it’s happening a bit in reverse, although I think it’s a bit easier to adapt from La Liga to the Premier League than from the Premier League to La Liga."
Saul had found things tough himself after leaving Spain for England, joining the Blues on loan from Atletico Madrid, but appears to have turned things around since the turn of the year.
There were no such teething problems for Ronaldo, though, either when he left Man Utd for Real Madrid in 2009 or when he returned to Old Trafford last summer via three years in Serie A.
The former Juventus forward is United's top scorer with 14 goals this season, meaning he has already scored more goals in half a season than Hazard has managed in the two-and-a-half years since his £89m move to the Bernabeu.
"You can do things here that you really can’t do in La Liga," Saul said, explaining "[in Spain] it’s much more tactical, whereas here it’s more physical and a bit crazier."
Hazard has scored just once for Real Madrid this season, in the Copa del Rey last-16 victory over Elche in January, and the forward was left on the bench for the quarter-final defeat away to Athletic Club.
Despite scoring 21 times in his final Chelsea season - including twice in the Europa League final as the Blues won the competition - he has just six Real Madrid goals to his name in more than 60 appearances.
By contrast, Ronaldo's sixth goal of his second Man Utd spell came against Atalanta in October - his eighth game since returning.
