Reus extended his Dortmund deal to 2019 this week, the extension also removing a clause in his contract that could have seen him snapped up cheaply at the end of the season.
A host of European powerhouses including Bayern Munich and Real Madrid had been lined with the Germany attacker, though he appears to have spurned their advances, despite Dortmund's terrible season in the Bundesliga.
Woeful form domestically saw Dortmund sit bottom of the table in the league's winter break, where they remained until a 3-0 win over Freiburg last weekend.
Reus' commitment to the cause will provide a huge boost to Jurgen Klopp's squad as they find themselves in an unfamiliar relegation scrap, and Watzke believes the gesture will see him go down in Dortmund folklore.
"If you decide for your club in such a situation, you are down at the bottom of the table, you have offers from the biggest clubs on earth, but nevertheless you decide for your club, thus resigning a lot of financial conditions, that are those players who will be later legends in their clubs," explained Watzke.
"Just like Uwe Seeler, who didn't go [from Hamburg] to Inter Milan, also other players, like [Steven] Gerrard at Liverpool.
"And now there is also the possibility, especially in the case of Marco, who is born here in this city."
