City put an end to Leeds' march
Leeds showed little bite and, when they did, it came some while later after Brown clipped Tevez.
Kolarov’s free-kick was deflected into the side-netting and Javi Garcia got forward to glance a header across goal from a corner.
Leeds belatedly tested Pantilimon when Ross McCormack forced the Romanian to palm away a free-kick in the last minute of the first half.
Brown was removed at half-time by Warnock, depriving the Leeds fans of one figure they love to hate but they turned their sarcasm on their unpopular manager.
They were soon doing that from a position of 3-0 down as Aguero combined with Silva and raced into the box before clipping a ball across goal for Tevez to volley in from close range.
There was little to entertain in most of the second half, although the Leeds supporters maintained their humour by cheering anything forward-thinking their side did as if they had scored.
Despite that their message was clear: they want Warnock out and they remain unhappy with the team’s inconsistency and the club’s unclear off-field picture.
Jack Rodwell came off the City bench and almost made an immediate impact as he headed onto the crossbar after Ashdown had parried a Yaya Toure shot.
The fourth City goal came after 74 minutes as Silva split the Leeds defence with a superb pass and Aguero turned and waited for the optimum moment to curl past Ashdown.
Another City substitute, Edin Dzeko, brought a good low save out of Ashdown as City cantered to victory.
Wiganmanager Roberto Martinez made seven changes, but his side was still too good for Huddersfieldand cruised through to the FA Cup quarter-finals for the first time in 26 years on the back of a 4-1 victory.
Winger Callum McManaman, a distant relative of former Liverpool striker Steve McManaman, and midfielder James McArthur were two players Martinez recalled and they rewarded the Spaniard with displays full of Premier League class.
McManaman struck a fine opening goal in the 31st minute and Arouna Kone tapped home a second shortly before the break to leave new Huddersfield manager Mark Robins with a difficult half-time team-talk in his first match in charge.
McArthur struck a brilliant third goal from the edge of the penalty area early in the second half and although Huddersfield substitute Lee Novak headed home just after the hour, it was not enough to trouble a Wigan side who are still chasing their first win in the Premier League this year.
The visitors soaked up a fair portion of late pressure but emphatically underlined their superiority when Kone thundered home a fourth goal in the closing stages.
FA QUARTER-FINAL DRAW
1 Everton or Oldham Athletic v Wigan
2 Manchester City v Barnsley
3 Manchester United or Reading v Middlesbrough or Chelsea
4 Millwall v Blackburn Rovers.
Ties to be played March 9th/10th.