A stunning away-day display ensured that one half of Manchester will be represented in the fifth round of the FA Cup.

It may have taken a slice of luck for Manchester City to succeed where United failed as referee Graham Poll's gaffe handed them the lead.

But their second-half dominance at Portman Road meant their meeting with another FA Barclaycard Premiership side - Newcastle - in three weeks' time was richly deserved.

Eyal Berkovic volleyed in the first goal just before the break after Poll had wrongly awarded a corner and Shaun Goater's 25th goal of the season, to climax a breathtaking break, all but sealed their passage.

Marcus Bent's sixth goal in seven games provided brief hope for George Burley's side.

That was blown away, though, as Goater added a third and strike partner Darren Huckerby claimed another, amazingly City's 84th goal of a barnstorming season, in a frantic finale.

Separated by just four places in the English ladder, City made a mockery of their lower status and indeed Ipswich's run of six victories in seven matches.

The visitors, beaten three times by Ipswich last season and relegated from the top-flight following the third, duly left Suffolk by extending their own spell to eight wins and a draw in their last nine.

Manager Kevin Keegan gave Danish international Niclas Jensen his full debut in place of the suspended Danny Tiatto while Huckerby earned a recall up front with Paulo Wanchope on international duty with Costa Rica.

City, the First Division leaders, started brightly and it took a precisely-timed intervention by Hermann Hreidarsson to halt a free run on goal for Shaun Wright-Phillips, in pursuit of Eyal Berkovic's pass.

Seconds later, Wilnis' hesitancy was exploited by Ali Benarbia, who stole the ball and released Huckerby, whose shot on the run was held low down by Andy Marshall.

But Ipswich's own fluent passing might have seen them take an eighth-minute lead as Jermaine Wright and Sixto Peralta worked an opening down the right and Marcus Bent flashed a drive narrowly over the top from the latter's centre.

With both sides looking to attack at every opportunity, play switched from end to end with regularity and Marcus Stewart and Shaun Wright-Phillips were both off target with long-range attempts.

Stewart turned provider in the 25th minute, when he coaxed a through ball into the stride of the breaking Martijn Reuser only for the Dutchman to fluff the chance with goalkeeper Nicky Weaver advancing, stubbing a hashed chip wide.

Two minutes later, Reuser ghosted in at the back post to meet Marcus Bent's deep cross, from a raid down the right, and Weaver did well to scoop his header round the post.

While the visitors continued to look dangerous on the counter it was Ipswich who were holding the premium on the chances during the first period.

And when Peralta sent Matt Holland beyond the City rearguard, Weaver kicked his low shot from the foot of his upright for a corner.

Argentinian midfielder Peralta, scorer of two goals in the last round against Dagenham and Redbridge, then flashed a volley wide as a Reuser corner was cleared to the edge of the box.

Despite their dominance, however, Poll's refereeing blunder handed Keegan's side the lead two minutes before the interval.

Benarbia's cross hit Jensen on the backside and cannoned out of play - but Poll awarded a corner, incensing both captain Holland and John McGreal, who confronted the official.

Meeting Benarbia's flag-kick on the full some 20 yards from goal, Israeli midfielder Berkovic thundered his effort through the crowd and past the combined efforts of Marshall, who got a hand to the ball, and Reuser on the left-hand post.

Having gone in front just before the break, City could have doubled their advantage three minutes after the restart.

Benarbia sent Shaun Goater racing clear and when the First Division's top scorer was foiled by Marshall's rush from goal, Huckerby's goalbound shot was blocked by Bramble.

Huckerby was only inches wide from City's next attack, glancing a header across goal from a Stuart Pearce cross.

If Ipswich had been warned, they did not heed it and the Premiership were two goals behind 20 minutes into the second half.

Wright's loose ball went straight to Jensen and the Dane strode forward before finding Benarbia, who, in turn, fed Goater for the striker to beat Marshall and guide in his 25th goal of the season.

Substitute Alun Armstrong went close to pulling a goal back as he sidefooted over and Stewart struck the bar in a goalmouth melee.

Then, seven minutes from time Ipswich gave themselves hope as Bent, seizing on a lay-off from Stewart, curled a shot past Weaver from 25 yards via a slight deflection.

Moments later, Armstrong's header was turned away at full stretch by Weaver.

But another clever assist from Benarbia killed off any hope as Huckerby's drive was parried by Marshall and Goater rose to head home his second.

Chasing the game, Ipswich conceded a fourth at the death as Richard Dunne's punt forward allowed Huckerby to beat the offside trap, round Marshall and fire into an empty net.

Teams

Ipswich: Marshall, Wilnis (Armstrong 65), Hreidarsson (Le Pen 80), McGreal, Bramble, Holland, Wright, Reuser (Clapham 53), Peralta, Stewart, Marcus Bent.

Subs Not Used: Sereni, Naylor.

Goals: Marcus Bent 83.

Man City: Weaver, Pearce, Wiekens, Dunne, Jensen, Horlock, Berkovic, Benarbia, Wright-Phillips, Goater, Huckerby.

Subs Not Used: Nash, Ritchie, Negouai, Killen, Dickov.

Booked: Dunne, Benarbia.

Goals: Berkovic 43, Goater 65, 86, Huckerby 90.

Att: 21,199

Ref: G Poll (Tring).