But, for the time being, they would settle for any tangible return on their vast investment, and a comprehensive win at Eastlands saw Manchester City comfortably into the quarter-finals of a competition that brought the club its last silverware nearly 34 years ago.
Roque two: City striker Santa Cruz celebrates scoring to make it 2-1
Better still for the men from Abu Dhabi, they saw Roque Santa score his first goal since an £18million move from Blackburn.
Other summer signings Joleon Lescott and Carlos Tevez were also on the scoresheet while Stephen Ireland and Michael Johnson did their bit for the homegrown brigade.
Johnson's goal was his first in more than two years after his promising career was disrupted by injury. City manager Mark Hughes said: 'I thought Roque was excellent. It's always important for strikers to score and get off the mark. I'm sure he'll grow into the role here now.
'And for Michael Johnson to score an outstanding goal is a huge lift for everybody at the club. He's been out of the game for too long but he's going to be like a new signing for us.'
Although Hughes made six changes, it would be unfair to say he fielded a weakened team in a competition he has taken seriously from the start.
In came Sylvinho for his debut and a first appearance since helping Barcelona beat Manchester United in the Champions League final in May, Santa Cruz, Pablo Zabaleta, Shaun Wright-Phillips, Vincent Kompany and Ireland.
High rise: Manchester City's Joleon Lescott, top right, heads in the third goal
It was the Irishman's first start since spending a night in hospital after leaving the field in the last round against Fulham a month ago complaining of feeling dizzy, but he was celebrating a goal inside three minutes.
Ireland coasted on to a pass from Wright-Phillips halfway into the Scunthorpe half and weighed up his options before curling a precise right-foot shot inside Joe Murphy's left-hand post.
At that stage Scunthorpe were so outclassed it was difficult to see any way back, but they stunned Eastlands with an equaliser from their first attack in the 26th minute.
Nigel de Jong was guilty of losing possession to Marcus Wi l l i a m s , w h o w a s t h e n released down the left flank by a combination of Paul Hayes and Jonathan Forte.
City failed to track Forte's run into the penalty box and he had the simple task of sidefooting in from eight yards out when Williams drilled a cross towards the far post.
It meant Shay Given had failed to keep a clean sheet for the eighth game in a row, but it almost got a whole lot worse for the City keeper.
Iron man: Jonathan Forte equalises for Scunthorpe
Hayes had a glorious chance to put the Championship side ahead, heading straight at Given after Forte had muscled Zabaleta off the ball near the corner flag.
In that moment their chance of an upset had disappeared. Normal service was resumed seven minutes before the interval when Santa Cruz claimed his first goal since scoring for Blackburn at Old Trafford in February.
De Jong returned a throw-in to Zabaleta, who found space down the right to cross to the back-post where Santa Cruz dropped off his marker, David Mirfin, to beat Murphy with a beautifully cushioned header into the far corner that looked a lot easier than it was.
All smiles: Joleon Lescott celebrates with his team-mates
Scunthorpe skipper Robert Jones got back to deflect Gareth Barry'sclose-range effort on to the outside the post but his withdrawal athalf-time was a big loss to the visitors.
City piled on thepressure and the only surprise was that they had to wait until the 56thminute for a third goal, Wright- Phillips sending over a corner fromthe right for Lescott to rise unchallenged for his second goal in asmany games.
One to watchVLADIMIR WEISS (Manchester City)
The midfielder, 19, is highly rated by Mark Hughes and has five Slovakia caps. He has been an unused substitute on several occasions this season, coming off the bench for extra time against Fulham in the last round of the Carling Cup and again last night when he excelled. We can expect to see much more of Weiss despite the stern competition at City.
The arrival of Vladimir Weiss only served to give City a fresh impetus,the young Slovakia midfielder tormenting Cliff Byrne with a mesmerisingperformance down the right.
It was Weiss's cross that set up Tevez to lunge in and score the fourth goal from close range before Johnson rounded it off in the 77th minute.
Scunthorpe boss Nigel Adkins said: 'We were still in the game at half-time but, let's face it, City's quality totally shone through in the second half.
'They've set out their stall to win the competition and they look like they can do it. The scoreline was probably what people expected before the game.'
MANCHESTER CITY (4-1-3-2): Given; Zabaleta, Kompany, Lescott, Sylvinho; De Jong; Wright-Phillips, Barry (Johnson 72), Ireland (Weiss 59); Tevez (Benjani 80), Santa Cruz. Booked: De Jong, Zabaleta.
SCUNTHORPE (4-4-2): Murphy; Byrne, Mirfin, Jones (Canavan 46), Williams; O'Connor (Hooper 68), Wright, McCann (Togwell 78), Woolford; Forte, Hayes.
Man of the match: Stephen Ireland.
Referee: Michael Oliver.
Chelsea whizkid Sturridge finally gets chance to impress Carlo in the CupCity's Bellamy escapes FA charge for attacking fan during Manchester derbyRobinho's return excites Mark Hughes as Man City striker is one week away
Explore more:People:Shaun Wright-Phillips, Roque Santa Cruz, Joleon Lescott, MARK HUGHES, Carlos Tevez, Joe Murphy, Paul Hayes, Shay Given, Nigel Adkins, Gareth Barry, Vincent KompanyPlaces:Ireland