Former Norwich City winger Luke Chadwick enjoyed a memorable return to Carrow Road on Tuesday night as he helped inflict the heaviest defeat of manager Paul Lambert's reign as manager.

Milton Keynes Dons cruised to a 4-0 victory in the Carling Cup second round, with winger Chadwick scoring twice, and the scoreline in no way flattered the League One leaders.

City fans were making their way out of the ground long before the final whistle as they once again witnessed a sub-standard cup-tie performance, amid a subdued atmosphere when compared to the hothouse that greeted the Premier League home opener against Stoke two days earlier.

Despite Lambert fielding a completely different eleven from the game against Stoke, it was still a strong City line-up with just one new signing, defender Daniel Ayala making his first start, and most of the side featured prominently in the Championship promotion campaign.

Chadwick, who spent two years with City as a player after arriving in 2006, gave MK Dons the lead in the 21st minute, with the highly-rated Sam Baldock making it 2-0 seven minutes later after an error by Adam Drury. The two players combined for goal number three on the hour as Chadwick struck again, and a mistake by Andrew Surman presented substitute Daniel Powell with the fourth goal in the 67th minute.

With just three minutes gone, MK Dons threatened through Dean Bowditch but his progress was blocked by the fit-again Zak Whitbread.

At the other end, goalkeeper David Martin gathered an effort from Aaron Wilbraham, playing against his former club.

An error in the 12th minute by Ayala gave Baldock an opening, but goalkeeper Declan Rudd was right behind his shot.

The Dons threatened again when Bowditch got the better of Russell Martin and crossed into the six-yard box, where Drury made a vital clearance.

But the visitors took the lead in the 21st minute through ex-Canary Chadwick. Stephen Gleeson made good headway to the right-hand corner of the penalty area, slipping the pass to Chadwick on his right, and the winger coolly tucked his shot past Rudd.

City were almost level inside 90 seconds when Simeon Jackson burst through, but 'keeper Martin raced off his line to take the ball off Jackson's toe.

In the 28th minute, there was another shock for the Canaries as Baldock made it 2-0. Drury was caught in possession just inside the Norwich half by Gleeson, who in turn found Baldock, who let fly with a powerful shot that whistled past the stunned Rudd.

Rudd was forced into action a minute later, saving from close range from Adam Smith after he got the better of Drury.

A cross from Drury was well gathered by goalkeeper Martin after Whitbread set the full-back clear, and Jackson had a shot deflected wide for City's first corner, five minutes before the break, but Surman's kick cleared the penalty area.

Surman had a shot deflected wide two minutes before the break, referee Haywood inexplicably awarding a goal-kick, which rather summed up the hosts' first 45 minutes.

Chadwick was showing some good touches and brought Rudd into action a minute after the break with a 20-yard effort. David Fox drilled a free-kick wide after Hoolahan was fouled, but it was Surman who finally brought some life into City's attacking play eight minutes after the break with a sizzling 30-yard drive that Martin had to tip over the bar. Still MK looked dangerous and Baldock set up Chadwick for a first time shot that went just over.

Hoolahan sliced a shot wide from Korey Smith's pass but on the hour, it was as good as over for City when Chadwick scored his second goal of the night. It was a superb effort as the former City man played a one-two with Bowditch and took the return in his stride before beating Rudd with a quality finish.

Lambert immediately replaced Hoolahan with Steve Morison and as City pushed forward, Korey Smith curled a shot over the top.

But the deficit became humiliating for the Canaries in the 67th minute when Surman's attempted backpass fell perfectly for substitute Powell, on the field for just four minutes, who tucked his shot past Rudd.

Chances of even a consolation goal went begging when Korey Smith sliced a shot wide from Morison's pass, and Wilbraham fired into the crowd. There was a final change for City when Ritchie de Laet replaced the hobbling Ayala, suffering from a knee injury, with 13 minutes left.

• Norwich City: Rudd, Russell Martin, Drury, Whitbread (Lappin, 74), Jackson, Surman, Hoolahan (Morison, 63), Fox, Smith, Wilbraham, Ayala (De Laet, 77). Subs (not used): Ruddy, Johnson, Holt, Bennett.

• MK Dons: David Martin, Smith, Lewington, Mackenzie, Gleeson, Potter, Bowditch (Powell, 63), Sam Baldock (O'Shea, 77), Williams, Ibehre (Balanta, 46), Chadwick. Subs not used: McLoughlin, Chicksen, Flanagan, Baldock.

• Referee: Mark Haywood

• Attendance: 13,009