The Germans turned on the second invading army in the Battle of the Masurian Lakes; it fled with heavy losses to escape encirclement. During the rest of 1914, commanding an Army Group, Hindenburg and Ludendorff staved off the projected invasion of German Silesia by dexterously moving their outnumbered forces into Russian Poland, fighting the battle of the Vistula River, which ended with a brilliantly executed withdrawal during which they destroyed the Polish railway lines and bridges needed for an invasion. When the Russians had repaired most of the damage the Germans struck their flank in the battle of Łódź, where they almost surrounded another Russian army. Masters of surprise and deft maneuver, the pair argued that if properly reinforced they could trap the entire Russian army in Poland. During the winter of 1914–15 they lobbied passionately for this strategy, but were rebuffed by "OHL".