“Romario was my idol, but Maradona is the best in history. Maradona did something unique with Napoli. Thanks to him, they won two scudettos [league titles], they've never achieved this since then," Rafael van der Vaart has told Tuttosport.
"Messi is a champion, but believe me, if he moved to a club like Hamburg, then yes, the team would have improved, but he would not have achieved success like Diego with Napoli and Argentina," the Dutchman added.
Well, we could only speculate about such things. Hamburg are currently playing in the Bundesliga 2, so Leo Messi's presence could've possibly boosted their chances of promotion at least.
As for Diego Maradona's Napoli, they were initially the stronger side than today's Hamburg so this comparison makes little sense.