English Premier League football leaders Chelsea beat second-tier Derby County 3-1 to reach the League Cup semi-finals, but the victory came at a cost with injuries to Kurt Zouma and Didier Drogba.
Eden Hazard and Filipe Luis, with his first goal for the club, put Chelsea in control on a rain-soaked night at Derby, before Craig Bryson replied for Derby in the 71st minute.
But the hosts' hopes of a comeback were extinguished when centre-back Jake Buxton was sent off for impeding substitute Loic Remy and Andre Schuerrle made the game safe with eight minutes to play.
Remy was only on the pitch because Drogba had been forced off by an ankle injury earlier in the second half, while Zouma was taken off on a stretcher in first-half injury time after colliding with goalkeeper Petr Cech.
There was a shock in the other quarter-final as misfiring Premier League side Southampton crashed out after losing 1-0 to third-tier Sheffield United at Bramall Lane.
It is Southampton's 5th straight loss in all competitions.
It is the second season in succession that United have reached the last four of a major tournament, following their run to the FA Cup semi-finals last season.
Beleaguered Liverpool face a tricky assignment at Championship leaders Bournemouth tomorrow, while Tottenham Hotspur host Newcastle United in the only all-Premier League tie of the round.