Hoffenheim drew a blank for only the second time this season as they lost top spot in the Bundesliga with a 1-0 defeat at Hertha Berlin.
With 31 goals in the preceding 11 games, it was a surprise to see Ralf Rangnick's side fail to score at least once in the Olympiastadion, but their coach had a simple explanation for it.
"We were only playing at about 70% of our ability today," he claimed.
That was still enough to "dominate the game most of the time", but a goal from Andriy Voronin ensured the home side took all three points and ended Hoffenheim's five-game winning streak.
"We are not machines," added Rangnick. "Nobody can expect my lads to play 100% week on week.
"I don't care about losing top spot, I am just annoyed that we have failed to get three points."
Hertha Berlin general manager Dieter Hoeness paid credit to his defense for emulating Stuttgart in nullifying the league's top scorers.
"They were world class today - you cannot get better than that," he said of central defenders Josip Simunic and Arne Friedrich.
Berlin have alternated between highs and lows all season but are now up to fifth in the table, and Friedrich hopes his side can now stay in the upper reaches.
"If we keep playing like we did against Hoffenheim, we can mix it with the top clubs, but we have also seen another side of us before and it is important that we do not get carried away," he told the Berliner Morgenpost newspaper.
"The win over Hoffenheim gives us a lot of self-confidence and our aim is to keep the next three points with us."
Berlin host fourth-placed Hamburg next Saturday while Hoffenheim are at home to seventh-placed Wolfsburg.
