Sheffield United have rallied, Brighton & Hove Albion cruised and Fulham lost their heads as the FA Cup produced another afternoon of high drama.
When the dust had settled second-tier Sheffield United were drawn to meet Manchester City, with the participation of Sunday's matchwinner dependent on City's generosity, and Brighton paired with a Manchester United side whose progress to the last four was gifted by their opponents' meltdown.
The Blades trailed twice before beating fellow Championship club Blackburn Rovers at Bramall Lane 3-2.
Premier League Brighton then brushed aside fourth-tier Grimsby Town 5-0 at the Amex.
With the draw made after that match Fulham seemed set to face the Seagulls, leading at Old Trafford 1-0 with less than 20 minutes left and in control.
Then Willian was sent off for handballing a goalbound shot on the line. Fulham protests led to their goalscorer Aleksandar Mitrovic being dismissed for pushing the referee Chris Kavanagh, and manager Marco Silva for attempting to influence the official as he looked at the VAR screen.
Bruno Fernandes converted the penalty, Marcel Sabitzer tapped in a few minutes later, and Fernandes added a third against the nine men to make it 3-1 in added time.
"I don't think so," Silva said of a potential long ban for Mitrovic.
"Of course in all moments we should control the emotions but we are human beings.
"Of course he pushed the referee but I didn't see that being so bad as you are saying, so I hope the people who are going to decide, decide with the fairness the moment deserves."
Until Fulham's implosion the dramatic moment of the day had appeared to be a stunning injury-time winner by Tommy Doyle.
The 21-year-old, whose grandfathers Mike Doyle and Glyn Pardoe both played at Wembley for Manchester City, booked the Blades' place at the stadium, which hosts both semi-finals, with a 25-yard drive.
However, Doyle will only be allowed to play if City, who beat Championship leaders Burnley 6-0 on Saturday, permit him as he is on loan from the Premier League champions.
United had trailed 1-0 and 2-1 to Rovers. Ben Brereton Diaz, from the spot, and Sam Szmodics had each put Rovers ahead, but an own goal by Sam Gallagher and an 81st-minute scuffed finish by Oli McBurnie earned the Blades parity before Doyle's clincher.
"For us to be in with a chance of automatic promotion and be in the semi-final of the FA Cup is an unbelievable achievement, and it is a big pat on the back for everyone at the club," United manager Paul Heckingbottom said.
"It's been a fantastic season so far and I am focused on capping it off, it could end up being an unbelievable one."
Playing against a team that had already beaten five sides from higher divisions, including top-flight Southampton, Brighton made the perfect start.
Deniz Undav got the first on six minutes and soon after the break went two-up after Irish teenager Evan Ferguson superbly controlled a pass from World Cup winner Alexis Mac Allister before scoring Albion's second.
The promising youngster struck again after 70 minutes before a Solly March header and a deflected shot from Kaoru Mitoma completed the scoring.
