... further injuries as midfielders Joe Cole (groin) and Mohamed Diame (knee) went off.
Sam Allardyce (who handed Andy Carroll his first start of the season): "Joe's shouldn't be too long.
"Mo's looked more serious - and until a scan we don't know - but (the medical department) are saying it may not be as serious as first thought.
"Still I think he would be out for a little while.
"When you let Negredo in with a free header in the first minute at the far post, there's nobody else to blame but your defenders.
"We got a really good response off that when Kevin (Nolan) scored, but unfortunately that was offside.
"We should have had a penalty in the second half. There's no doubt about that, but the way things are going for me, I think if one of Man City punched one of our players in the face in the box we wouldn't get a penalty.
"Forty (points) is the safe zone over more than 10 years now. It's got to be 22 points minimum for me in the last 16 (games)."
Allardyce has been trying to strengthen his options in the transfer market and was frustrated at missing out on striker Lacina Traore, who now appears set to join Everton on loan from Monaco.
Asked if he is likely to make any signings before next week's match at Chelsea, Allardyce said: "I wouldn't have a clue at the minute. Every time I get a new signing somebody else f****** takes him."
WEST HAM 0 MAN CITY 3
30. Costel Pantilimon 38. Dedryck Boyata 6. Joleon Lescott 33. Matija Nastasic 22. Gael Clichy 15. Jesus Navas 79'' 14. Javi Garcia 63'' 25. Fernandinho 64. Marcos Lopes 9. Alvaro Negredo 16. Sergio Aguero 65''
Subs: 1. Joe Hart 5. Pablo Zabaleta 10. Edin Dzeko 13. Aleksandar Kolarov 79'' 17. Jack Rodwell 63'' 26. Martin Demichelis 35. Stevan Jovetic 65''
City hammered West Ham 6-0 in the first leg of the semi-final two weeks ago and no mercy was spared again on Tuesday night at Upton Park.
Not for the first time this season it was City''s dynamic duo of Sergio Aguero and Alvaro Negredo who did the damage in this 3-0 win.
Negredo opened the scoring after two minutes with a close-range header and he rounded off the win in the second half after Aguero had made it 2-0.
Negredo and Aguero have now scored an incredible 45 goals between them for City this term.
They will now be hoping that Manchester United overturn their first-leg deficit against Sunderland to set up a mouthwatering derby final on March 2.
West Ham, who were booed off the pitch, were always going to be up against it after the manner of their first-leg defeat, but the main thing that will worry manager Sam Allardyce was his team''s lack of fight on what was a depressing night for Hammers fans inside a less than half-full Upton Park.
Allardyce will also be concerned by the fact that Mohamed Diame and Joe Cole suffered injuries.
Those among the 14,390 fans who turned up and bought a programme read rallying cries from Allardyce, captain Kevin Nolan and co-owner David Gold.
Gold called for character and guts, but instead he got complete capitulation.
With 175 seconds gone Marcos Lopes was given a couple of yards of space down the left. He whipped in a pin-point cross for an unmarked Negredo who headed home.
City''s noisy travelling support started singing about Wembley. The home crowd sat in silence while Allardyce slumped into his chair with his arms folded.
Nolan thought he had equalised straightaway, but unlike Negredo he timed his run poorly and his header was ruled out for offside.
Aguero made Roger Johnson, who has spent most of the season at the wrong end of the Championship on loan at Sheffield Wednesday, look a fool, nipping the ball past the defender, but luckily for West Ham the shot from City''s Argentinian assassin flew a yard wide.
Aguero and Negredo were combining superbly. Aided by the quicksilver teenager Lopes and Jesus Navas, City were a pleasure to watch going forward.
West Ham were making it easy for the visitors too, though.
Matt Taylor dallied on the ball on the half way line and City piled bodies forward on the break. Jussi Jaaskelainen just got a hand to Aguero''s shot and the hosts breathed again.
Andy Carroll, making his first start of the season, woke from his slumber to power a header high and wide in a rare West Ham attack.
The inevitable second came with 23 minutes on the clock and once again City had Lopes to thank.
The 18-year-old galloped forward from the halfway line and slipped past two West Ham players before finding Aguero via the boot of James Tomkins.
A comedy of errors played out as first Razvan Rat, and then Taylor slipped, allowing Aguero time to chip the ball past an onrushing Jaaskelainen.
Aguero was tearing around the pitch straight after as he attempted to find a third. His took his exuberance too far on one occasion though, stamping on Tomkins to earn a booking that could have easily been a red.
Normally such a challenge would have caused outrage among the home support, but they remained quiet, apparently disinterested in what was unfolding.
Carroll tried to belt the ball at goal in frustration at being flagged offside but it ended near the corner flag.
The England striker''s night came to a close at half-time when he was replaced by Carlton Cole.
West Ham were short on luck as well as quality.
Joe Cole hobbled off with an injury. Stewart Downing came on in his place.
Joleon Lescott then took down Ravel Morrison in the box, but referee Chris Foy waved play on.
West Ham offered little more going forward and they found themselves 3-0 down just before the hour.
Negredo did nearly all the work this time. The Spaniard held off the challenges of three West Ham players before chipping the ball over Jaaskelainen from the tightest of angles.
West Ham finally got some good news when Pellegrini brought Stevan Jovetic on for Aguero, who was applauded off by the home and away fans.
Pellegrini kept Negredo on the pitch and the move looked to backfire as Tomkins sent the Spaniard flying with a late challenge.
Foy took no action but Negredo returned to the pitch shortly after some treatment on the sidelines.
There was no such luck for Allardyce, though, who saw key player Diame carried off on a stretcher shortly before the final whistle, which was greeted by loud booing from the home support.
FA Cup draw
Sunderland v Kidderminster
Bolton v Cardiff
Southampton v Yeovil
Huddersfield v Charlton/Oxford
Port Vale v Brighton
Nottingham Forest v Preston
Southend v Hull
Rochdale v Sheffield Wednesday
Arsenal v Coventry
Stevenage v Everton
Wigan v Crystal Palace
Chelsea v Stoke
Manchester City v Watford
Bournemouth v Liverpool
Birmingham v Swansea
Sheffield United v Fulham
•Ties to be played January 24-26