Leipzig moved to seven points from Bayern Munich, which knocked down Eintracht Frankfurt 5-2 on Saturday, after losing two points against Freiburg last weekend.
Werner ended a four-game period without scoring and increased his league tally to 24 goals, only surpassed by Bayern Munich talisman 27 Robert Lewandowski.
In truth, it could have been worse because the descent threatened Mainz. Yussuf Poulsen missed a babysitter after Werner’s pass in the first half and Christopher Nkunku dragged his shot when he was alone on goalkeeper Florian Muller, also in the first half.
Poulsen, however, scored earlier.
It wasn’t a bother given their respective places in the standings, but since the German first division returned last week after a two-month stoppage, local teams have generally struggled to play without fans.
They have won three of 18 matches, losing 10 times. Earlier on Sunday, eighth place Schalke fell 3-0 at home to Augsburg, who had been in the bottom five, and on the last kickoff, Koln needed goals in the 88th and 91st minute to save a draw at home against the last Dusseldorf.
Games behind closed doors are one of the measures applied to avoid mass gatherings.
On Tuesday, second place Borussia Dortmund hosts Bayern Munich at Der Klassiker in Germany.