Sunderland's relegation from the Championship is looking likely once more after they lost at home to Sheffield Wednesday on Saturday.
Chris Coleman's side sprung a shock on Friday with a 4-1 win at Derby County, but a 3-1 reverse to the Owls has left them five points adrift of safety with only six games left.
Coleman said: "If you look at the stats over the 90 minutes, we had 20-odd shots, 10 corners, they had one, we had much more possession, it was one of those were you think how have we lost 3-1?"
Derby responded to that setback with a win at Preston North End, but Bristol City and Sheffield United suffered blows in their bids to secure a play-off spot.
SURVIVAL ODDS BLEAK FOR THE BLACK CATS
Sunderland aimed to pick up where they left off following their emphatic win at Derby, but they were punished for failing to make the most of first-half chances.
Lucas Joao broke the deadlock 59 minutes in and, although George Honeyman's header restored parity two minutes later, Wednesday snatched victory through Tom Lees and Atdhe Nuhiu.
Sunderland are now level on points with bottom side Burton Albion, who looked set for a vital win over Middlesbrough until Britt Assombalonga equalised in the 90th minute at the Pirelli Stadium.
QPR took a step towards guaranteeing their safety, though, as a goal and two assists from Matt Smith inspired them to fight back from 1-0 down to beat Norwich City 4-1 and move two points behind the 14th-place Canaries.
Nottingham Forest's match with Barnsley was postponed due to a waterlogged pitch.
PLAY-OFF RACE HOTS UP
Middlesbrough's draw at Burton gave the Blades a chance to move into the final play-off spot, but they were denied by a late Cardiff City equaliser at Bramall Lane.
Anthony Pilkington's stoppage-time volley snatched a 1-1 draw for Neil Warnock's second-place side, who are eight points above Fulham, ensuring promotion remains firmly in their hands.
Bristol City's hopes of a top-six finish took a blow, too, as Neal Maupay secured a deserved 1-0 win for Brentford with just 10 minutes left at Ashton Gate.
Derby ended an eight-game winless run and jumped up to fifth, Tom Lawrence's free-kick after Alan Browne missed a penalty sealing a 1-0 win at Preston.
Millwall are one two points outside the play-offs after battling to a 2-2 draw at Ipswich Town.
