BERLIN, Oct. 17 (Xinhua) -- Bayern Munich showed no mercy to league newcomers Arminia Bielefeld as Thomas Muller and Robert Lewandowski scored a brace each to secure a 4-1 away win in the Bundesliga's fourth round of matches on Saturday.
The German record champions took the reins from the start, breaking the deadlock only eight minutes into the match as Muller exchanged passes with Lewandowski before tapping home from very close range.
The Bavarians pressed relentlessly and doubled their lead with 25 minutes gone when Leon Goretzka's build-up work allowed Lewandowski to slot home from the edge of the box.
The Poland international produced another promising opportunity for Bayern four minutes later when he forced Bielefeld goalkeeper Stefan Ortega into action.
Lewandowski eventually wrapped up his brace with a deflected shot to beat Ortega just before half-time.
After the restart, Muller sealed his brace after drilling Lewandowski's cross into the roof of the net after six minutes of the second half.
Bielefeld slightly found back their form and were able to reduce the arrears in the 59th minute as Fabian Klos' square pass found Ritsu Doan, who made no mistake to slot home past Bayern keeper Manuel Neuer.
Doan continued to cause danger for Bayern as he rattled the woodwork in the 70th minute.
Bayern, meanwhile, had to conclude the game with ten men as Corentin Tolisso received his marching orders after felling Klos when he was through on goal.
Despite being outnumbered for the remainder of the match, Bayern stood firm and secured their third win of the season.
With this victory, the defending champions move up to 2nd place in the table, while Arminia Bielefeld slipped to 14th position.
Elsewhere, Wolfsburg and Borussia Monchengladbach shared the spoils after Wout Weghorst's equalizer canceled out Jonas Hofmann's opener.
Cologne take on Eintracht Frankfurt and struggling Schalke encounter Union Berlin to complete the fourth round of matches on Sunday.