A run to the Champions League final and the sale of Mario Gotze give Dortmund's chief executive reason to believe the decision not to sell the Pole was the right one
The latter figure represented an astonishing 86 per cent season rise compared to the previous year - another record high for the club.
"In the end, my conclusion is that; I do not want to be too positive but I think that Borussia Dortmund are well positioned for the future," Watzke told reporters.
"But we know as well that we are now in a crucial phase in terms of our sustainability in the sport.
"That is the only reason we have not sold Robert Lewandowski. All of us at the club - [general manager] Michael Zorc, Jurgen Klopp, me, the management and all other bodies - were all in agreement, because we want to bring the best possible team to the pitch this year.
"Therefore we had to make compromises."
Lewandowski, who reportedly has received a €3.5 million pay rise last week, was frustrated throughout the close-season as the club, he claimed, reneged on a deal which would see him move to Bundesliga rivals Bayern Munich.
However, the 25-year-old, who is in the final year of his contract, has drawn a line underneath the dispute and says he is ready to play for Dortmund.