Wolverhampton Wanderers secured promotion to the Premier League for next season after Fulham conceded a stoppage-time equaliser on Saturday.
Nuno Espirito Santo's side play Birmingham on Sunday, but Fulham's 1-1 draw means that now only Cardiff can theoretically catch the runaway Championship leaders.
Aleksandar Mitrovic's 70th-minute goal for Fulham had looked like putting Wolves' party on hold but Neal Maupay's last-gasp header for Brentford sent Wolves up.
Wolves have won 28 of their 42 league games this term to seal a return to the top flight after a six-season absence.
The finished bottom of the Premier League in 2011-12 with just 25 points, then suffered a second straight relegation the following season by finishing 23rd in the Championship.
However, Wolves rebounded by winning the League One title in 2014, and just missed the Championship promotion playoffs on goal difference in 2015.
But the club got the boost it needed in July 2016 with the takeover of Chinese investment group Fosun International, and have now returned to the top flight.
Wolves managing director Laurie Dalrymple credited Santo, a former Porto and Valencia coach, with spearheading the team's revival since taking charge last year.
"What he has brought in has been fantastic," Dalrymple told Sky Sports. "He came in, he changed the playing style. We've recruited well and he's galvanized the group really strongly in a very short space of time.
"And very, very quickly he had us playing a different style of football than we'd been accustomed to, and a brand of football that was delivering results really quickly."
There has been some disquiet around Wolves because Santo and several players are represented by Jorge Mendes, who sold his minority share to Fosun subsidiary to enable the takeover, and rival clubs have complained to the Football League about the relationship between Wolves and the Portuguese agent.
Earlier in the Championship on Saturday, Cardiff left it late but kept themselves on course for an automatic promotion place with a 2-0 win at Norwich.
Neil Warnock's side had to dig deep to earn a vital three points at Carrow Road, which moved them above Fulham and into second place.
Kenneth Zohore squeezed the ball past Angus Gunn in the 86th minute before Junior Hoilett's goal in added time ensured Cardiff's two-game losing streak was brought to an end.
Cardiff now lead Fulham by a single point, though the Bluebirds also have a game in hand.
Middlesbrough stormed into the playoff places after coming from behind to beat Bristol City 2-1 at the Riverside Stadium.
Milan Djuric volleyed the visitors into a 13th-minute lead before George Friend levelled for Boro five minutes later. Daniel Ayala then headed home the winner in the 68th minute, moving Middlesbrough up to fifth while also denting Bristol City's own top-six hopes.
Veteran striker Steve Morison struck his fifth goal of the season for Millwall as they came back to draw 1-1 against fellow playoff hopefuls Sheffield United in the early kick off.
Leon Clarke opened the scoring for the Blades in the 74th minute, but Morison equalised instantly to grab his side a point. The sixth-placed Lions remain unbeaten in the league since New Year's Day and Sheffield United, who are ninth, have not lost at home since late January.
Derby slipped out of the top six, but Burton moved off the bottom and to within five points of safety after a 3-1 victory over the Rams at the Pirelli Stadium.
Liam Boyce tapped home from close range to put the hosts in front after 24 minutes, but their lead did not last long as David Nugent equalised moments later. Luke Murphy curled a beautiful effort past Scott Carson to restore the Brewers' lead just before the break and Lucas Akins added a third in the 68th minute.
Oli McBurnie's added-time equaliser secured a vital 2-2 draw for Barnsley at home to fellow strugglers Bolton.
Gary Gardner scored from 10 yards midway through the first half for the Tykes before Adam Le Fondre levelled from the spot after 82 minutes. Craig Noone thought he had won it for Bolton three minutes later, but McBurnie had the final say to keep Barnsley within two points of the 21st-placed Trotters.
Sunderland slipped to the foot of the table and remain six points below Bolton after drawing 2-2 at Reading.
Liam Kelly gave the Royals the lead from the penalty spot after Lee Camp brought down Jon Dadi Bodvarsson in the box after 20 minutes. Paddy McNair fired home a stunning equaliser for the Black Cats just after the break before Lee Cattermole's first goal since August 2014 put the visitors in front in the 66th minute.
Yann Kermorgant restored parity for Reading with 11 minutes remaining to leave Chris Coleman's side on the brink with three games left.
Ben Brereton's late penalty and Joe Lolley's goal in added time secured an unlikely 2-1 win for Nottingham Forest against Ipswich, who had led through Grant Ward's first-half header.
Elsewhere, Callum Robinson's double sealed a 2-1 win for Preston against QPR, who had Matt Smith on the scoresheet, while Jordan Rhodes scored the only goal in Sheffield Wednesday's 1-0 win at Hull.
Information from The Associated Press was used in this report.