Cardiff sealed the Championship title despite David Edgar's injury-time header snatching a vital point for struggling Burnley in a 1-1 draw.
The Bluebirds confirmed their passage to the top flight with a stuttering goalless draw against Charlton in midweek but a swashbuckling opening half, capped by Craig Conway's superb 27th-minute finish, suggested they would claim the first second-tier crown in their history in some style.
Meanwhile, Watford won 4-0 at home to struggling Blackburn to keep their hopes of finishing in the second automatic promotion spot alive.
Troy Deeney scored twice before Almen Abdi and Matthew Briggs sealed a comfortable win which leaves the Hornets four points adrift of second-placed Hull. The result also means Blackburn are just two points and two places above the relegation zone.
Huddersfield gave their hopes of staying in the Championship a huge shot in the arm as they were inspired to a 3-0 win over Millwall by Jermaine Beckford's double.
Beckford, making his 250th league appearance, struck a goal in each half to sandwich James Vaughan's neat finish early in the second period as the Terriers moved three points clear of the drop zone.
Elsewhere, Brighton consolidated their play-off place with a 6-1 thumping of Blackpool.
Ashley Barnes scored a late brace after Will Buckley, Matthew Upson, Andrea Orlandi and David Lopez had all got on the scoresheet for Gus Poyet's side, with Blackpool's only response being Dean Hammond's 53rd-minute own goal.
Leicester lost momentum in their promotion push as they slipped out of the top six with a 2-2 draw against play-off rivals Crystal Palace.
Andy King cancelled out Danny Gabbidon's first-half strike before Palace took the lead again in the 67th minute through Stephen Dobbie. However, Chris Wood equalised five minutes later.
That result meant Bolton leapfrogged Leicester into the final play-off place thanks to a 2-1 win over Middlesbrough.
Chris Eagles put the Trotters ahead five minutes into the second half before Kieron Dyer's header levelled the score soon after.
It was not long before Bolton were back in front, though, when Marvin Sordell converted from the spot following Jonathan Woodgate's foul on Lee Chung-yong. Woodgate was later sent off.
Wolves slipped into the bottom three after a late, late 2-1 defeat at Charlton. Jonathan Obika's 90th-minute goal earned the home side the win after Dorian Dervite's earlier goal was cancelled out by Kevin Doyle's header.
Peterborough remain above the relegation zone on goal difference after they were beaten 3-1 at Derby.
Craig Bryson, Chris Martin and Richard Keogh all scored for the Rams, with Grant McCann's 64th-minute penalty the visitors' consolation.
Derby goalkeeper Frank Fielding was sent off for the foul that led to the spot-kick, but Posh could make no further inroads against the ten men.
Elsewhere, Hayden Mullins' 71st-minute goal for Birmingham was enough to end new Leeds boss Brian McDermott's two-game winning run as the Yorkshire club were beaten 1-0 at St Andrew's, and Barnsley remain in the bottom three after they drew 0-0 against Nottingham Forest.
Sheffield Wednesday and Ipswich drew 1-1 in the other game, with Leroy Lita cancelling out Jay Tabb's early goal for the visitors.
Nottingham Forest were frustrated by relegation-threatened Barnsley at the City Ground as a 0-0 draw left them two points adrift of the play-off places.
The hosts hit the woodwork three times, through Henri Lansbury, Andy Reid and Billy Sharp, while Barnsley goalkeeper Luke Steele made some fine saves.
Information from the Press Association was used in this report