There was no Christmas cheer for the Sky Blues as Blackpool ran out deserved winners at Bloomfield Road.
Iain Dowie's men struggled to reproduce their excellent away form this season and were on the back foot within 28 minutes when Wes Hoolahan converted a penalty.
Kevin Kyle was given a straight red card for an elbow on home skipper Shaun Barker two minutes later.
The home side doubled their lead on the hour mark as Michael Flynn fired past Dimi Konstantopoulos before Kaspars Gorkss powered a header into the top corner.
Substitute Scott Vernon compounded the Sky Blues' misery two minutes from time when he raced clear and slotted home.
The return of Kyle was the only change to the side which battled to a 1-1 draw at Southampton last weekend as Leon McKenzie failed to shrug off a knee problem.
City survived an early scare when Flynn's 25-yard free-kick took a deflection and cannoned back off the post.
Skipper Michael Doyle then fired a set-piece from a similar distance over the bar while Kyle headed wide from a teasing free-kick from David McNamee.
Former Sky Blue Andy Morrell was proving a nuisance upfront for the Seasiders and went agonisingly close to opening the scoring midway through the half when he headed Hoolahan's left-wing cross narrowly wide from eight yards.
Good vision from Michael Hughes then found Jay Tabb in behind the home defence on the right but his cut-back was hacked away by Ian Evatt with Kyle and Michael Mifsud in close attendance.
Blackpool had appeals for a penalty waved away by referee Anthony Taylor when Ward appeared to push Morrell just inside the area.
But the official was in no doubt moments later as Hungarian defender Gorkss was brought down by McNamee and Hoolahan confidently sent Dimi Konstantopoulos the wrong way from the spot with a low drive to the keeper's left.
Things then went from bad to worse for the visitors on the half-hour when Kyle was dismissed with Taylor claiming the Scottish striker caught Barker with his elbow.
A good save from Konstantopoulos kept out the influential Morrell on the stroke of half-time before a good block from Elliott Ward denied the striker five minutes into the second period.
Barker should have doubled the home side's advantage from Hoolahan's resultant corner but he headed wide despite being allowed a free header in the area.
An unusually quiet Mifsud saw two efforts blocked and Leon Best's deflected drive was comfortably held by Blackpool 'keeper Paul Rachukba as City looked for a response.
Their task was made all the harder in the 65th minute, though, when Flynn latched onto a long ball from Evatt just inside the area and planted a powerful shot beyond Konstantopoulos.
The result was put beyond doubt in the 72nd minute when a close-range header from Gorkss skimmed the head of Gary Borrowdale before flying into the top corner.
Substitute Scott Vernon then found himself in behind the City back-line and coolly slotted the ball past Konstantopoulos from eight yards to complete the rout.
Blackpool: Rachubka, Barker, Evatt, Gorkss, Crainey, Jorgensen, Flynn (Welsh, 74), Hoolahan, Taylor-Fletcher (Fox, 46) Burgess, Morrell (Vernon, 83). Subs: Slusarski, Jackson.
Goals: Hoolahan (28 pen), Flynn (65), Gorkss (72), Vernon (88)
Booked: None
Coventry City: Konstantopoulos, McNamee, Ward, Turner, Borrowdale, M Hughes (S Hughes, 68), Doyle (c), Tabb, Mifsud (Osbourne, 76), Best (Adebola, 76), Kyle, Subs (Not Used): Gray, Marshall (GK).
Booked: Doyle (34, foul), McNamee (40, foul), Best (70, foul), Tabb (90, unsporting behaviour)
Sent-off: Kyle (30, violent conduct)
Attendance: 8,690 (1,192 Coventry)
