Moustapha Bayal Sall's second-half header earned St Etienne a 1-0 Ligue 1 win at Rennes.The defender scored the decisive goal in the 74th minute to help his side move up to fifth place, three points off third-spot Nice.Defeat was Rennes' second loss in a row and left them in a congested mid-table, only two points behind their opponents.The victory was only the visitors' third league win since November and, in a match of few clear-cut chances, was secured when Bayal Sall rose to head home a Renaud Cohade's free-kick from the right.