Sheffield United moved into first place in the Sky Bet Championship after coming from behind to defeat 10-man Swansea 2-1.
The Blades struggled in the first half and were behind due to Florian Bianchini's early goal.
However, manager Chris Wilder made three substitutions at halftime, and his brave decision paid off as Rhian Brewster and Harrison Burrows' penalty helped Sheffield United go two points ahead of Leeds in the league.
Leeds can reclaim the top spot by winning against Norwich at home on Wednesday.
Swansea faced a difficult task after Harry Darling was sent off just moments after Brewster's equalizer early in the second half for a reckless challenge on the forward.
The game opened up as Swansea's Liam Cullen had a shot saved by Michael Cooper while Gustavo Hamer hit the side-netting at the other end.
Swansea took the lead after seven minutes when Bianchini headed in the rebound from a free-kick taken by Matt Grimes.
Despite their strong start, Swansea's performance was a stark contrast to their uninspiring loss to Cardiff in the previous match. Josh Tymon tested Cooper with a shot, showing more intent in the first 13 minutes than in the entire previous game.
Sheffield United struggled to create clear chances, with a Jack Robinson header going over the bar. They were lucky to avoid conceding a penalty after Myles Peart-Harris was seemingly fouled in the box by Rhys Norrington-Davies, who had already been cautioned.
The half ended with missed opportunities for both sides as Cullen and Hamer failed to capitalize on their chances.
United quickly equalized at the start of the second half through a goal by Brewster, who had a successful loan spell at Swansea five years ago.
Swansea were reduced to 10 men shortly after as Darling was shown a straight red card for a reckless challenge on Brewster.
The winning goal came in the second half when Burrows converted a penalty after Tyrese Campbell was brought down in the box by Josh Key, who was playing out of position due to Darling's absence.
Hamer received his 10th booking of the season for a foul and will miss upcoming matches against Hull and Derby.
Sheffield United's victory condemned Swansea to their fourth defeat in five games.