Chelsea through to FA Cup

        

    Ba volleyed in a Juan Mata pass four minutes into the second half to send Chelsea into the semi-finals and deny runaway Barclays Premier League leaders United a Wembley clash with derby rivals Manchester City.The opening 20 minutes were even, with United fielding Antonio Valencia at right-back and Phil Jones in midfield, the latter tasked with nullifying the threat of Eden Hazard in particular. Petr Cech made a stunning 61st-minute save from Javier Hernandez and Chelsea held on to stay on course for a fifth FA Cup triumph in seven seasons, with City their last-four opponents on April 14.Hernandez, who has been prolific against the Blues with seven goals in 10 games, created space for himself in the area but slipped before he could shoot. Despite the close attention of Jones, the impressive Hazard was Chelsea's most dangerous outlet and he fashioned an opportunity for Ba to shoot, only for David de Gea to save with his feet.Both sides made seven changes for their second game in three days, with Wayne Rooney absent for the visitors after picking up a groin problem on England duty in Montenegro last week. Rio Ferdinand was in the United starting XI, but John Terry and Frank Lampard were only on the bench for Chelsea's second of six games in 16 days.