Sead Kolasinac's second-half strike was enough for Schalke to win 1-0 at Mainz on Sunday for just its second Bundesliga away victory of the season.
Kolasinac struck five minutes after the break, playing a one-two with Guido Burgstaller when he was surrounded by a host of defenders before running on to shoot inside the right corner.
The goal settled the visitors while Mainz was forced to risk more going forward.
Pablo De Blasis sent Jhon Cordoba through but Schalke goalkeeper Ralf Faehrmann gathered the ball.
Nabil Bentaleb should have wrapped it up late but failed to get the better of Jonas Lossl in a one-on-one with the goalkeeper.
Schalke moved ninth while Mainz stayed 12th, among four teams just two points above the relegation zone.
Bayern Munich was hoping to stretch its lead to 13 points with a win at Borussia Moenchengladbach in the late game.