Genoa extended their unbeaten run in Serie A to four matches but were held to a goalless home draw by Empoli after midfielder Darko Lazovic had been sent off.Midfielder Lazovic was shown a second yellow card for his foul on Manuel Pasqual in the 34th minute of a game devoid of much goalmouth action.Neither side created a clear-cut scoring chance in the first period until Alberto Gilardino went closest to breaking the deadlock for Empoli when his low angled shot was well saved by Genoa goalkeeper Mattia Perin.Genoa midfielder Miguel Veloso's shot from outside the area was brilliantly saved in the 56th minute by Empoli keeper Lucasz Skorupski, who also kept out Nikola Ninkovic's shot.