DUBLIN, Sept 7 (Reuters) - A freakish own goal from central defender Nikola Milenkovic earned Ireland a 1-1 home draw with Serbia as the visitors missed a string of chances after Sergej Milinkovic-Savic fired them ahead in their Group A World Cup qualifier on Tuesday. The result left Serbia second in the group on 11 points from five games, two behind leaders Portugal who leapfrogged them into pole position with a 3-0 win in Azerbaijan earlier in the day. Ireland goalkeeper Gavin Bazunu produced a string of superb saves after Milinkovic-Savic headed in Dusan Tadic"s corner in the 20th minute, having denied Serbia"s top scorer Aleksandar Mitrovic three times. The 19-year-old keeper also kept out efforts from Dusan Vlahovic, Nemanja Radonjic and Filip Kostic before Milinkovic-Savic turned villain in the 87th minute with a comical error. He blasted a simple goal-mouth clearance into Milenkovic who could not get out of the way, giving Ireland only their second point in the qualifiers after Stephen Kenny"s side scraped a 1-1 home draw against Azerbaijan on Saturday.