Russell Martin headed straight at Schwarzer from the resulting corner, before David Fox collected a booking for scything down Dembele.
Birmingham's misery was compounded in the 79th minute as Robinson was shown a straight red card by the referee Andy Woolmer for scything down Wilson.
But their night, and in particular McNaughton's, went sour as he was sent off for scything down Hylton a minute after half-time.
Valencia's Rúben Vezo was shown a red card in the 80th minute for scything down Shatov as the Russian midfielder threatened to add to Zenit's lead.
A measure of this was found in first Mohamed Elneny being booked – for pulling at Meyler – and then Giroud, for scything down Curtis Davies, one of the trio of centre-backs in Hull's 3-5-2 formation.
Urbano Ortega was cautioned in the 40th minute for scything down Des Bremner, but for most of the first half Barça, in fairness, did not need to resort to skulduggery because they defended superbly.
Guardiola's side, who have now won five successive matches against Madrid - including a similarly emphatic 6-2 matling athehe Bernabeu in 2009, added a fifth goal in stoppage-time through Jeffren before Madrid lost Sergio Ramos to a straight red card for scything down Lionel Messi.
Poyet's men picked up two yellows to Newcastle's three in a feisty opening half, although their battling midfielder Lee Cattermole escaped a booking despite scything down Daryl Janmaat in the first minute.
Camp proved equal to efforts from Ward and Dawkins, while the loud contingent of 1,391 away fans had a heart-stopping moment when Brett Pitman's swirling cross slipped out of the unchallenged Grant's gloves like a bar of soap, and Derby defender Jake Buxton was cautioned for scything down the lively Rantie as the first period drew to a close.
Busquets was also cautioned for scything down Ramires after Juan Mata was withdrawn for Salomon Kalou.
