Juan Mata from scoring a dramatic winner.
Did you know? Ramires is the first player ever to score against United for the same team in three different domestic competitions in the same season. He also netted against the Reds in the earlier league and Capital One Cup meetings, both in October at Stamford Bridge.
Opposition boss: Rafa Benitez has had many tussles with Sir Alex in the past and there was some controversy when he claimed the United boss refused to shake his hand after the first encounter - something the Reds boss denied. After impressing with Spanish club Valencia, Benitez won the Champions League with Liverpool but was less successful at Inter Milan. Following a wait for a return to the limelight, he was the surprise choice as 'interim manager' at Chelsea which caused great consternation among the club's support.
Star man: Chelsea have a wealth of creative talent at their disposal and Eden Hazard seems to be recapturing his best form. The Belgian, allegedly also a United target when at Lille, helped change the game at Old Trafford and his strike was beautifully executed. Another superb solo effort for Belgium in midweek confirms he is somebody at the top of his game at present.
Sub-plots: Any Benitez versus Ferguson head-to-head is bound to attract attention and there is plenty at stake in West London. Both teams will have played 48 hours earlier and, of course, Manchester City lie in wait in the semi-finals. Chelsea, of course, knocked United out of the Capital One Cup but only after Hazard's injury-time penalty forced extra time.