Manchester City's array of world stars had too much in all departments for Norwich City as they maintained their unbeaten start to the Premier League season with an emphatic victory at the Etihad Stadium.

The league leaders inflicted the heaviest defeat of Paul Lambert's reign as manager with a flurry of goals in the second period after taking a narrow 1-0 lead into the half-time interval.

After some dogged resistance by the Canaries, Sergio Aguero gave the hosts a 32nd-minute lead when he threaded a shot through a forest of legs after good work by full-back Micah Richards.

It was 2-0 six minutes into the second half when a free-kick from Samir Nasri appeared to catch goalkeeper John Ruddy by surprise and he could only help it on its way into the net.

The third goal came in the 68th minute when Yaya Toure curled a splendid shot out of reach of Ruddy.

Norwich had a scent of a chance early in each half when Steve Morison, then Elliott Bennett, went clear, but failed to capitalise.

Morison, however, gave the noisy travelling fans something to celebrate when he pulled a goal back nine minutes from time, heading in from David Fox's cross for his fifth of the season.

Worse was to come for Lambert's men, however, as Mario Balotelli scored Manchester City's fourth two minutes from time and fellow substitute Adam Johnson scored the fifth in stoppage time.

Norwich boss Lambert made two changes after the 2-1 home win over Queens Park Rangers.

With Ritchie de Laet ruled out by a recurring back problem, Kyle Naughton returned at right-back.

And Elliott Bennett returned to the starting line-up at the expense of striker Simeon Jackson.

Defender Zak Whitbread was named among the substitutes – his first involvement in the senior side since suffering a hamstring injury at Chelsea in August.

There were also two changes to the Manchester City side from their last Premier League fixture, the 1-1 draw at Liverpool six days earlier.

Kolo Toure was preferred to Joleon Lescott at the back after his outing at Arsenal in the Carling Cup on Tuesday, and Edin Dzeko replaced James Milner. The two England internationals were among the substitutes.

Before kick-off, a minute's applause was held in memory of Wales manager Gary Speed following his death last weekend at the age of 42.

When play got under way under grey skies, Morison conceded a free-kick in the opening minute when he caught Richards on the head with a high boot.

With just two minutes gone, Dzeko demonstrated his threat to the Canaries when he whistled a low shot 18 inches wide of Ruddy's left-hand post.

At the other end, Morison showed his attacking intent when he flashed a volley just wide from an unlikely distance.

In the 10th minute, Norwich had a real opening when Morison did well to get the better of both Kolo Toure and Kompany and found himself with a clear run at Hart. His control let him down, however, and he allowed the ball to run just far enough ahead for Hart to block his run and the ball squirted away to safety.

The home side were back on the offensive and as Ruddy fumbled a shot by Aguero, it was left to Barnett to hack the ball clear.

Silva should have done better after 16 minutes when he volleyed over from Manchester City's best chance and, as the Canaries counter-attacked, Morison nodded down Surman's cross but there was no one to take advantage.

With City packing midfield, Pilkington was back in his wide left role, like a second left-back at times, with Surman tucked inside him, and they had nine outfield players behind the ball for most of the time as the leaders tried to find a way through.

Kolo Toure's ball sent Richards away on the right but his cross went begging as it flew across the six-yard box.

Surman was booked after 24 minutes for a foul on Silva, the first time World Cup final referee Howard Webb had reached for his yellow card.

On the half-hour, Dzeko nutmegged Russell Martin and let fly but his shot was diverted out for a corner by Tierney.

The goal the home side had threatened came in the 32nd minute, however, when Aguero found a way through the packed defence.

Richards took the ball to the byline on the right and pulled it back to Aguero, who twisted and turned, and eventually managed to thread a shot low through a forest of legs, the last of them belonging to Crofts.

It was a soft goal after some dogged defending, but Nasri missed a good chance to make it 2-0 when he blazed over, then Dzeko volleyed high and wide from Aguero's delicate chip.

Barnett did well to block Nasri's shot at the expense of another corner as the one-way traffic continued.

In first half stoppage time, Norwich had a rare opportunity when they forced a corner but Surman's inswinging kick was headed away by Dzeko.

• Half-time: Manchester City 1, Norwich City 0

Within two minutes of the restart, Bennett had the scent of a chance when he was put clear on the right, but a heavy touch took the ball too wide and the opportunity was gone as he hooked it behind.

After 51 minutes, however, the leaders moved 2-0 ahead thanks to an error from Ruddy. Crofts was penalised for a foul on the Manchester left and Nasri took the free-kick, curling it towards the Norwich six-yard box where it seemed to take the goalkeeper by surprise and he succeeded only in helping it into the net.

Another Nasri free-kick posed problems as Dzeko went for a header, before Johnson hacked clear.

Ruddy made a fine double save moments later, but the home side were well on top and it took a block by Tierney to prevent Aguero scored the third.

With an hour gone, Lambert made a double change when Hoolahan replaced Pilkington and Holt came on for Bennett.

But midway through the half, it was effectively game over as Yaya Toure scored Manchester City's third.

A corner on the left was worked to Toure, who had enough space to curl a perfect right-foot shot beyond the reach of Ruddy.

There was an immediate change from the home dug-out as Adam Johnson replaced Nasri.

Another of the scorers was substituted after 72 minutes when Aguero made way for Balotelli.

Dzeko fired over the top from another chance and then, with 13 minutes left, Lambert made his final change with Fox replacing Johnson.

A rare opening came the Canaries' way when Barnett and Holt just failed to get a touch on Fox's free-kick.

They did get a goal back with nine minutes left, however, when Morison scored his fifth of the season.

Fox was the provider with a nicely-flighted cross from inside the penalty area, and Morison beat Hart with a firm header.

The hosts made their last change when De Jong came on for Dzeko.

Surman shot just wide as the Canaries enjoyed something of a late rally.

Substitute Balotelli made it 4-1 two minutes from time, knocking the ball in after Adam Johnson's trickery, but only at the second attempt after Ruddy had blocked his initial effort.

As the game entered stoppage time, Adam Johnson rolled in a fifth to complete a comprehensive victory.

• Result: Manchester City 5, Norwich City 1

• Manchester City: Hart; Richards, Kompany, Kolo Toure, Clichy; Silva, Yaya Toure, Barry, Nasri (Adam Johnson, 69); Aguero (Balotelli, 72), Dzeko (De Jong, 82). Subs (not used): Pantilimon, Lescott, Savic, Milner.

• Norwich City: Ruddy; Naughton, Barnett, Russell Martin, Tierney; Bennett (Holt, 60), Crofts, Bradley Johnson (Fox, 77), Surman, Pilkington (Hoolahan, 60); Morison. Subs (not used): Rudd, Whitbread, Jackson, Wilbraham.

• Referee: Howard Webb

• Attendance: 47,201

• Goals: Manchester City: Aguero (32), Nasri (51), Yaya Toure (68), Balotelli (88), Adam Johnson (90). Norwich: Morison (81)

• Bookings: Norwich: Surman (24)