Sheffield Wednesday turned in a shocking opening 45 minutes as they slumped to a 3-1 defeat at Hillsborough against Birmingham City in the Championship.
Goals from David Davis and a Jota brace put the Blues in total control at half-time, with Marco Matias shown a straight red card before the break.
Lucas Joao pulled a goal back but any chance of an Owls recovery were shattered when they were reduced to nine men for the final 20 minutes when Daniel Pudil was sent off for two bookings.
Matias partnered Atdhe Nuhiu in attack, meaning there was no place for striker Jordan Rhodes - the subject of transfer speculation this week before the January window closed - in the match-day squad.
Wednesday manager Jos Luhukay said: “It was a disappointing day for us. It goes wrong, whatever can go wrong today in the first half.
“We went two goals behind where we made very big mistakes for the first and second goal.
“After that we also had the red card. I don’t know what the referee has seen from that situation. From my position it was just a hot moment between two players but the referee decided for the red card so for us, it was very hard.
“Then, before half-time, they get the third goal.
“It was mentally not so easy to come back in the game. At half-time we spoke and said that we must stay together.
“We came back to try in the last 45 minutes and we made it 3-1. Then after we had the second red card so what went wrong today also happened in the second half.”
Captain Glenn Loovens was also recalled for the Owls, with Jordan Thorniley and winger Ross Wallace on the bench.
And it was Matias who had the first chance of the game, pouncing on a loose ball, driving forward, but firing just over David Stockdale's crossbar.
The Owls had kept clean sheets in their last three league outings, but they conceded after just eight minutes and it was a horrendous mix-up which gifted the Blues their goal.
A right-wing cross looked to be comfortable for Frederico Venancio, but he tried to chest the ball to goalkeeper Joe Wildsmith - who had come out to claim the ball - and Davis slipped in to prod home in front of a stunned Kop.
And it got worse for the Owls, as Wildsmith somehow fumbled a long-range strike from Jota, allowing the ball to bounce into his goal after just 20 minutes.
It prompted manager Jos Luhukay to haul off defender Loovens - go 4-4-2 - and bring on another attacker in Lucas Joao.
The Owls' afternoon turned toxic on 38 minutes, Matias shown a straight red card for an off-the-ball incident with Blues' Cohen Bramall.
And in seven minutes of first-half stoppage time, Wildsmith parried a low shot into the path of Jota who fired home into an empty goal.
Substitute Joao drilled home a reply for Wednesday on 54 minutes, but the hosts were reduced to nine men with 20 minutes remaining when Daniel Pudil was shown a second yellow card.
Joao was a willing runner, but Birmingham were content to see out the remainder of the game keeping possession.
In a rare Blues attack, Jeremie Boga forced Wildsmith into a one-handed save, low to his right.