article_snippet: The 24-year-old shakes hands with former team-mate Wayne Rooney (left) after the game . '
article_snippet: The Arsenal star celebrates with full back Hector Bellerin, but admitted it was tough to play against Manchester United . '
highlights_snippet: The England striker left to join Arsenal last summer .
  
highlights_snippet: The 24-year-old admitted it was hard to score against his boyhood team .