 High-flying Valenciennes missed a golden opportunity to take fourth spot in Ligue 1 after being held to a goalless draw by struggling Paris Saint-Germain at the Stade Nungesser.Lyon overcame a spirited PSG side in the capital to extend their lead at the top of the table, Sidney Govou's goal the clincher.Two goals in the opening 20 minutes set Paris Saint-Germain on the way to three much-needed points at Strasbourg, a victory that lifted "Les Parisiens" well clear of the relegation zone.