Gary Neville saw red but Manchester United's second string still disposed of Barnsley 2-0 whilst Blackburn and Portsmouth hit five and four respectively. Manchester United were already two goals to the good with strikes from Danny Welbeck and Michael Owen in each half when Neville was dismissed just after the hour mark.
But even with ten men the Premier League team had too much quality for the Championship outfit in front of a sell out crowd at Oakwell.
Portsmouth shrugged off their poor league form to thump Stoke 4-0 at Fratton Park.
Frederic Piquionne struck twice and set up another for Danny Webber before Kanu completed the rout to make it 11 goals from their three matches in the competition so far.
Another all Premier League clash saw Tottenham progress to the quarter finals following a 2-0 home win over Everton.
Flu hit Blackburn had a comfortable 5-2 win over 10-man Peterborough at Ewood Park.
The hosts took the lead through a Morten Gamst Pedersen free-kick before Chris Whelpdale headed an equaliser.
But further strikes from Michel Salgado Benni McCarthy and a late penalty from Nicola Kalinic saw Rovers ease through.
Villa's American keeper Brad Guzan then saved three spot-kicks to help his side progress 3-1 in a penalty shoot-out.