Sky Sports pundit Roy Keane has identified the biggest weakness in one current Manchester United star, despite praising how “brilliant” he has been this season. Manchester United punched their ticket to the FA Cup final after a dramatic penalty shootout win against Coventry City on Sunday at Wembley. The Red Devils looked all but certain to reach the final after taking control of the semi-final tie with a 3-0 lead in the second half. However, United suffered a mega collapse in the second half and Coventry City rallied back into the contest to send the tie to extra time and penalties. Casemiro …