Manchester City consigned beleaguered West Ham to a second hammering inside four days by romping to a 6-0 victory in the first leg of their League Cup semifinal on Wednesday, with Alvaro Negredo leading the rout with a clinical hat trick.

Sam Allardyce's visitors were always facing a daunting task at the Etihad Stadium, where City have shown dominant form, winning all 10 Premier League games and walloping Wigan 5-0 earlier in the League Cup.

And their resistance was broken after just 12 minutes, when Yaya Toure's defense-splitting pass down the middle fell onto the shoulder of Negredo, who lashed a left-footed volley past Adrian into the bottom corner.

The West Ham keeper pulled off two superb saves to deny efforts from David Silva and Samir Nasri, and after Yaya Toure returned to the pitch after hobbling off with a worrying looking injury, it was 2-0 on 26 minutes.

Negredo was the man on target once again, combining superbly with strike partner Edin Dzeko in a one-two before sliding home an angled finish.

Toure proved he had shaken off his knock when he made it 3-0 five minutes before the break, when he won possession on the halfway line and charged towards the Hammers' goal, with Roger Johnson backing off too much to allow the Ivory Coast star time to slam a right-footed shot past Adrian.

The visitors finally got their first shot on target in first-half stoppage time, but Mohamed Diame's 20-yard drive was easily saved by Costel Pantilimon.

Allardyce sent on Carlton Cole for Modibo Maiga at the interval, giving the striker his 250th appearance for the club.

But City's sheer dominance continued after the restart, with Negredo finishing off a fantastic flowing move involving Nasri and Silva on 49 with a first-time left-footed strike into the bottom corner for his treble.

Dzeko proved a menace to the visiting defense all night, and capped a fine personal display with City's fifth goal on the hour mark, sidefooting home from close range after a cross from Gael Clichy on the left flank.

Manuel Pellegrini made three substitutions in the closing stages, including withdrawing Negredo to a standing ovation from the home fans on 80, while Adrian's fine diving save briefly denied Dzeko a second goal of the night.

Dzeko had the last laugh, however, smashing home a sixth goal in the dying minutes to leave the visitors well and truly hammered.

With City having one foot in the final, the possibility of an all-Manchester affair at Wembley is still on the cards, with United trailing Sunderland 2-1 ahead of their semi-final second leg at Old Trafford.