Manchester City kept their quadruple hopes alive after coming back from two goals down to win 3-2 at Swansea City in the FA Cup quarter-finals thanks to Sergio Aguero's controversial late header.
Pep Guardiola's men looked to be heading out of the competition at the hands of second-tier opposition, but three goals in the final 21 minutes saw City come back from the brink, as Aguero – who appeared to be offside – nodded in the late clincher.
Although the Premier League champions initially looked bright, a confident Matt Grimes penalty put Swansea in the ascendancy and they doubled their advantage with an exceptionally worked Bersant Celina goal against his former club.
The visitors upped the ante after the break and pulled one back through Bernardo Silva, before an Aguero penalty went in off goalkeeper Kristoffer Nordfeldt.
And, just when Swansea looked to have held on to force extra-time, Aguero completed the comeback two minutes from the end to send City to Wembley.
City made a fine start and went close three times in the first 15 minutes, but Swansea capitalised soon after – Grimes coolly dispatching a penalty after Fabian Delph tripped Connor Roberts.
It was 2-0 before the half-hour mark as Swansea brilliantly carved through City and Nathan Dyer teed up Celina, who found the top-right corner with a curling effort from just inside the box.
City were back in it in the 69th minute when substitute Aguero saw a shot come back off Jay Fulton's face and the Argentina striker subsequently teed up Silva for a fine outside-of-the-foot finish.
Guardiola's side were level 12 minutes from the end, with Aguero's penalty – after Cameron Carter-Vickers was adjudged to have tripped Raheem Sterling – coming back off the post and going in off the unlucky Nordfeldt.
With City piling on the pressure, there was an air of inevitability about the winner, which arrived when the prolific Aguero met Silva's cross with a well-placed header into the bottom-left corner.
What does it mean? Curious absence of VAR costs Swansea
The focus is likely to fall on the absence of VAR after Aguero's contentious winner. The technology is being used in the competition and was available at the Liberty Stadium in the FA Cup last season, but after Swansea's relegation to the Championship, the Football Association are reported to have opted against continuing to equip the ground with the system.
Sterling's introduction gives City added drive
Silva and Aguero were decisive with their respective goals and assists, but Sterling made a huge difference after coming off the bench in the second half. He ran at Swansea's defence, won a penalty – in itself a bone of contention – and used the ball well.
Mahrez fails to grasp opportunity
By no means a regular starter, Riyad Mahrez was named in City's line-up and given the chance to impress, but he failed to do so. Aside from an early header, which he probably should have buried, the winger offered precious little and was eventually replaced by Aguero in a pivotal change from Guardiola.
City travel to struggling Fulham on March 30 as their title tussle with Liverpool resumes, while the Swans go to Nottingham Forest in the Championship on the same day.