BERLIN, Jan. 17 (Xinhua) -- Bundesliga leaders Bayern Munich opened up a four-point advantage in the standings after Thomas Muller's winner helped them edge in-form Freiburg 2-1 in the league's 16th round on Sunday.

The German record champions caught a bright start on home soil and caught Freiburg flat-footed with just seven minutes played when Robert Lewandowski made the most of Muller's build-up work to score his 21st goal of the season.

Bayern kept Freiburg's defense busy but wasn't able to extend its lead as neither Serge Gnabry nor substitute Leroy Sane was able to beat Mainz goalkeeper Florian Muller.

After the restart, Hansi Flick's men started where they left off as Lewandowski rattled the crossbar before Leon Goretzka hammered the rebound into arms of goalkeeper Muller at the hour mark.

Freiburg punished Bayern's wastefulness in front of the target only moments later when substitute Niels Petersen, who had only entered the field 25 seconds earlier, restored parity with a diving header at the far post following a corner.

The frontrunners responded in style and grabbed the 2-1 lead after Muller finished from Sane's assist.

Bayern remained on the front foot and continued to create opportunities but Freiburg had the best chance after Petersen hit the woodwork in the dying seconds of the game.

"We played courageously and could have made it 2-0 or 3-0. I am happy with the outcome and also with how the team played. Now we have to continue on this path in Augsburg and Schalke," said Bayern head coach Hansi Flick.

Said Freiburg head coach Christian Streich, "After we conceded the goal we played really well. We did everything and with the substitutions we had a lot of offensive power on the pitch. A 2-2 draw would not have been undeserved."

Elsewhere, in the farewell game of defender David Abraham, a second-half brace from Luka Jovic paved the way for Eintracht Frankfurt's 3-1 victory over bottom side Schalke.