 Complete the following phrase:  Arsenal returned to form in December, starting with a 31 win over Sunderland, with Joel Campbell and Aaron Ramsey scoring either side of goals at either end from Olivier Giroud. Arsenal then traveled to Olympiacos, where they had failed to win in their last three games, with their last win in Greece coming in 1998. Fears were erased by a Giroud hat-trick, putting Arsenal through and demoting Olympiacos into the Europa League, only for Arsenal to draw holders Barcelona, who had knocked Arsenal out in the 2010 quarter finals and in 2011 at the same stage. The Spanish side also beat the Gunners in the 