Cardiff are on the brink of ending their 51-year wait for promotion to the English top-flight after Rudy Gestede's double helped clinch a 3-0 win over 10-man Nottingham Forest on Saturday.
Heidar Helguson's ninth goal of the season had given Cardiff the lead before Darius Henderson was sent off for elbowing the Iceland striker and Gestede then sealed the win with his second half brace.
Watford's 3-2 defeat at Peterborough means Championship leaders Cardiff are now 12 points clear of the third-placed Hornets with four games remaining.
A draw against Charlton on Tuesday will be enough to secure the Welsh club's promotion to the Premier League.
Hull are on course to join Cardiff among the elite after Robert Koren's late winner sealed a 2-1 win at Ipswich.
Koren headed home Robbie Brady's cross in the 83rd minute after Ipswich substitute Anthony Wordsworth had cancelled out Brady's first-half penalty.
Victory for the Tigers lifts them six points clear of Watford in the race for automatic promotion.
Watford may have to settle for a spot in the play-offs after their surprise loss at struggling Peterborough.
Danny Swanson broke the deadlock with a cool finish in a one-on-one situation and Dwight Gayle doubled their advantage on the hour mark.
Lee Tomlin was instrumental in Gayle's goal and the two combined again for the third.
The latter was brought down by last man Marco Cassetti, who accrued a red card for his troubles, and Tomlin curled home the free-kick.
Although Mark Yeates and Fernando Forestieri pulled back a couple of goals for the Hornets, it did not alter a result which has huge implications at both ends of the table.
Brighton got their play-off push back on track as they ended a three-match winless run with a comfortable 2-0 victory at Middlesbrough.
Two second-half goals from Spanish duo Andrea Orlandi and David Lopez secured the Seagulls their first away win in five attempts that moved them up to fifth.
Bolton moved into the play-off places for the first time this season after Craig Davies's late penalty earned a win at bottom of the table Bristol City.
Dougie Freedman's men went ahead inside the opening two minutes thanks to Liam Fontaine's own goal but were pegged back by Steven Davies' leveller after the break.
The visitors snatched the points when Craig Davies struck home the spot-kick after David Ngog was brought down in the area by Matthew Bates.
Elsewhere, Leeds beat Yorkshire rivals Sheffield Wednesday 2-1 in Brian McDermott's first match as Elland Road boss.
Charlton won 6-0 at nine-man Barnsley and Blackburn eased their relegation fears with a 2-0 win over Derby.
Blackpool beat Burnley 1-0 and Huddersfield won 3-1 at fellow strugglers Wolves.