Named after Georg von Derfflinger, a German field marshal during the Thirty Years' War, "Derfflinger" was commissioned on 1 September 1914. A dockyard crew transferred the ship from Hamburg to Kiel, via the Skagen. The ship was assigned to the I Scouting Group at the end of October. Damage to the ship's turbines sustained during trials prevented the ship from seeing active service until 16 November. On 15 December, the ship took part in the raid on Scarborough, Hartlepool and Whitby. She was also present during the battle of Dogger Bank on 24 January 1915. The ship was hit once by a 13.5-inch shell from one of the British battlecruisers; in response, she heavily damaged . Repair work was completed by 16 February, but "Derfflinger"s starboard turbine was accidentally damaged on 28 June, and the ship was again in the dockyard until August. On 24 April 1916, "Derfflinger" took part in the bombardment of Yarmouth.