Mainz coach Thomas Tuchel concedes the club may struggle to hang on to rising star Andre Schurrle.
Schurrle was the matchwinner as Mainz edged out Kaiserslautern 2-1 on Sunday to maintain their 100% record after three matches in the Bundesliga.
And with Real Madrid already reported to be taking a keen interest in the 19-year-old Tuchel admits he may be tempted away from the Bruchweg Stadion in the not too distant future.
"We all know the situation here that we have to sell our top talents now and again," said Tuchel. "But that will only happen to a top four club."
Schurrle has a contract until 2013 with Mainz, but is unlikely to see out that deal, although he has promised to stay put for the remainder of the season.
"I am not going to move in the winter break and will definitely be staying in Mainz until next summer," he said.
As for Sunday's game, which saw Mainz join Hoffenheim at the top with a perfect record, the matchwinner was simply happy to have provided the fans with the result they wanted.
"This derby is the most important game for the fans here and I am delighted that we were able to give them something back with a win," he said to the Mannheimer Morgen newspaper.
Kaiserslautern coach Marco Kurz was disappointed that it was not his side joining Hoffenheim at the top, especially after they took the lead.
"We had hoped for more, but have got to recognise that Mainz's victory was the result of their strong spell of pressure," he said. "It is a shame that it did not work out."